No, they aren't .blb's, and I don't expect people to ever end up building with this game mode, I pretty much just plan to host a few select builds with it, if it ever does get finished.
The money everywhere's the generic cash wad the snipers drop when they die. Each 'monster' drops a certain amount and awards a certain amount of 'xp', which eventually builds up to give you levels, which only really give a 2% damage reduction, nothing interesting.