--- a/bitten/build/svntools.py
+++ b/bitten/build/svntools.py
@@ -13,12 +13,61 @@
 import logging
 import posixpath
 import re
+import shutil
+import os
 
 log = logging.getLogger('bitten.build.svntools')
 
 __docformat__ = 'restructuredtext en'
 
-def checkout(ctxt, url, path=None, revision=None, dir_='.', verbose=False):
+class Error(EnvironmentError):
+    pass
+
+def copytree(src, dst, symlinks=False):
+    """Recursively copy a directory tree using copy2().
+
+    If exception(s) occur, an Error is raised with a list of reasons.
+
+    If the optional symlinks flag is true, symbolic links in the
+    source tree result in symbolic links in the destination tree; if
+    it is false, the contents of the files pointed to by symbolic
+    links are copied.
+
+    Adapted from shtuil.copytree
+
+    """
+    names = os.listdir(src)
+    if not os.path.isdir(dst):
+        os.makedirs(dst)
+    errors = []
+    for name in names:
+        srcname = os.path.join(src, name)
+        dstname = os.path.join(dst, name)
+        try:
+            if symlinks and os.path.islink(srcname):
+                linkto = os.readlink(srcname)
+                os.symlink(linkto, dstname)
+            elif os.path.isdir(srcname):
+                copytree(srcname, dstname, symlinks)
+            else:
+                shutil.copy2(srcname, dstname)
+        except (IOError, os.error), why:
+            errors.append((srcname, dstname, str(why)))
+        # catch the Error from the recursive copytree so that we can
+        # continue with other files
+        except Error, err:
+            errors.extend(err.args[0])
+    try:
+        shutil.copystat(src, dst)
+    except WindowsError:
+        # can't copy file access times on Windows
+        pass
+    except OSError, why:
+        errors.extend((src, dst, str(why)))
+    if errors:
+        raise Error, errors
+
+def checkout(ctxt, url, path=None, revision=None, dir_='.', verbose=False, shared_path=None):
     """Perform a checkout from a Subversion repository.
     
     :param ctxt: the build context
@@ -28,18 +77,27 @@
     :param revision: the revision to check out
     :param dir_: the name of a local subdirectory to check out into
     :param verbose: whether to log the list of checked out files
+    :param shared_path: a shared directory to do the checkout in, before copying to dir_
     """
     args = ['checkout']
     if revision:
         args += ['-r', revision]
     if path:
-        url = posixpath.join(url, path.lstrip('/'))
-    args += [url, dir_]
+        final_url = posixpath.join(url, path.lstrip('/'))
+    args += [final_url, dir_]
 
     cofilter = None
     if not verbose:
         cre = re.compile(r'^[AU]\s.*$')
         cofilter = lambda s: cre.sub('', s)
+    if shared_path is not None:
+        # run checkout on shared_path, then copy
+        shared_path = ctxt.resolve(shared_path)
+        checkout(ctxt, url, path, revision, dir_=shared_path, verbose=verbose)
+        try:
+            copytree(shared_path, ctxt.resolve(dir_))
+        except Exception, e:
+            ctxt.log('error copying shared tree (%s)' % e)
     from bitten.build import shtools
     returncode = shtools.execute(ctxt, file_='svn', args=args, 
                                  filter_=cofilter)

--- a/doc/commands.txt
+++ b/doc/commands.txt
@@ -734,25 +734,30 @@
 Parameters
 ----------
 
-+--------------+-------------------------------------------------------------+
-| Name         | Description                                                 |
-+==============+=============================================================+
-| ``url``      | URL of the repository.                                      |
-+--------------+-------------------------------------------------------------+
-| ``path``     | The path inside the repository that should be checked out.  |
-|              | You should normally set this to ``${path}`` so that the     |
-|              | path of the build configuration is used.                    |
-+--------------+-------------------------------------------------------------+
-| ``revision`` | The revision that should be checked out. You should         |
-|              | normally set this to ``${revision}`` so that the revision   |
-|              | of the build is used.                                       |
-+--------------+-------------------------------------------------------------+
-| ``dir``      | Path specifying which directory the sources should be       |
-|              | checked out to (defaults to '.').                           |
-+--------------+-------------------------------------------------------------+
-| ``verbose``  | Whether to log the list of checked out files (defaults to   |
-|              | False).                                                     |
-+--------------+-------------------------------------------------------------+
++-----------------+-------------------------------------------------------------+
+| Name            | Description                                                 |
++=================+=============================================================+
+| ``url``         | URL of the repository.                                      |
++-----------------+-------------------------------------------------------------+
+| ``path``        | The path inside the repository that should be checked out.  |
+|                 | You should normally set this to ``${path}`` so that the     |
+|                 | path of the build configuration is used.                    |
++-----------------+-------------------------------------------------------------+
+| ``revision``    | The revision that should be checked out. You should         |
+|                 | normally set this to ``${revision}`` so that the revision   |
+|                 | of the build is used.                                       |
++-----------------+-------------------------------------------------------------+
+| ``dir``         | Path specifying which directory the sources should be       |
+|                 | checked out to (defaults to '.').                           |
++-----------------+-------------------------------------------------------------+
+| ``verbose``     | Whether to log the list of checked out files (defaults to   |
+|                 | False).                                                     |
++-----------------+-------------------------------------------------------------+
+| ``shared_path`` | An optional shared directory to check the sources out in,   |
+|                 | which will be reused for each subsequent build. This is     |
+|                 | relative to the project directory, so for standard usage    |
+|                 | set it to something like ``../trunk``                       |
++-----------------+-------------------------------------------------------------+
 
 
 Examples