I'll try to add few thoughts, since I've been working a lot also on Pluto system. Since I'm not experienced Linux guy, I could easily be missing something but anyway :
1. for a good start, I think working SVN and sqlcvs would be just fine
2. enhancement should be entered in coordinated way - For example under Pluto, where I helped a bit with Motion wrapper. I've contacted corresponding developers and explained what I'd like to add. Then he approved my work, I took down SVN source, compiled just new binary for Motion Wrapper and add it to my formal release. Then I tested it in my environment and then applied those changes into SVN - "official" testers did try it and it was in next release.
3. Same mechanism could be used for sqlcvs. I know this would narrow contributions, but again maybe better than nothing at all...
Currently we're not getting any enhancements into sql database or in source code, so maybe this would be improvement. And later, if community grows, we can take another steps.
What I'm currently also missing very badly is developers discussion... If you notice, I have several question regarding (how to best implement this, how to efficiently add this and to do some brainstorming on some future additions and how to implement them, or to learn important details about LMCE & Pluto internals etc..)...