KDE is also a large project with separate subprojects. I thought it might be a good idea to look at their structure. Here are some instructions: http://websvn.kde.org/tags/KDE/3.90.1/kde-common/svn/svn_instructions.txt?revision=660709&view=markup The instructions points to the tutorial: http://developer.kde.org/documentation/tutorials/subversion/index.html Here is the repository: http://websvn.kde.org/ Browsing the tags, I find the main releases of KDE, but I don't easily see the version numbers of the underlying projects. This baffles me slightly. But it seems to work well (doesn't it?). Regarding boost sandbox: I think it is good to be able to checkout one directory to get the trunk of everything. I.e. The subprojects shall not contain separate trunk/branches/tags. How about a trunk with the two subdirectories Boost and Sandbox? The Boost directory would contain libraries that are to be part of the next official Boost release, and the Sandbox other libraries. /$ (disclaimer: I'm new to both Boost and Subversion)