I've always wanted an actual deathmatch mod for TF2 that isn't team DM, but all vs all.
And not just friendly fire because the hit detection is horrible and half the game mechanics like flamethrowers and buildings don't work. I suppose it's a lot of work tho, and I don't know much about Python. But if you'd like to look into it perhaps taking a look at the NPC bosses' code and
this would help. Perhaps
this as well.
Also I guess an option would be to just cut engie and spy out completely, since it would be pretty wonky with disguises and sentries in dm anyway.