During elego's SvnDay in Berlin today, the topic of "committing part of a file" came up (during stefan2's talk about TortoiseSVN (future) features). As Michael suggested, it would be nice if this could someday become a feature of core svn.
It just so happens that one of my colleagues (svn user) was bugging me about the same thing recently. So I did some searching on prior work / discussion within subversion. Here's an interesting post from way back (the thread unfortunately died of pretty quickly): http://svn.haxx.se/dev/archive-2006-07/0817.shtml (I'm not volunteering, just putting the information out here in case someone wants to discuss this ...) -- Johan