I believe this is sort of already built in to OA. I know you can replace weapons, but I don't think you can move them around. Speaking of which, compatibility with OA would be great.
Edited 53 seconds after the original posting.

Another idea I have been thinking about recently is a modification of One Flag.

Instead of a neutral flag that is brought to the enemy base, make a central specific spot, that when the player is standing in, it will gradually convert the flag to their team color, something like 10% conversion every two seconds or something. A visual flag color change would be helpful too, gradually changing the flag color from blue to red and vice versa. Kind of similar to RegenCapture mode in Sauerbraten. Both bases will have access to the area to convert the flag, and once converted, it can be brought to the appropriate base to score a point. However, if captured by the enemy team, it first must be converted to the appropriate team color.

@themuffinator if you want it I'd be more than happy to to share the source code of 'The Dead Simple' (TDS) mod with you to integrate it with 'level up'.
I think that it can add a lot of versatility to the mod. Because most of the ideas discussed here are gametype and weapon modification related and TDS is more about organizing different styles of gameplay.