I would go SVN too, partly because I'm used to it, partly because update logs can be useful to see who has done what, when and why. They can also be abused for lulz. (See Archie's image)
As for the project, fuck yeah! Source project for sure, and definitely set in the HL universe to avoid to much coding. That's not to say we couldn't have coding if the need arose. A POV sequel would be very cool, and definitely hasn't been done before.
The thing is, USS Darkstar was a classic GoldSource mod with no coding or custom skins or anything. All they had were a few new sounds and the maps, and they managed to pull of an environment and story as far removed from Black Mesa as you can get (without coding and custom models :P)
What could I bring to the projectMy crappy maps. I'm not a great Source mapper, but this project could help me improve my skills with you guys being able to edit my maps and give feedback and advice.
My crappy models. I'm learning Blender, having completed a couple of models now, but again, a long way off professional so this would be a learning project.
My manly voice. Got a Blue Microphones Snowball which is decent enough quality for voice acting.
My handsome face. I'm not afraid to get it out there. Video updates and interviews are kinda my thing.