Nice thread,if this kicks off,I would like to see some ideas and use them when MW2 comes out from private matches!
My ideas-
Care Frenzy- Simple enough,all players are only allowed to use a knife and care package killstreaks,perks should be disabled (if that option is available in MW2) If you get a care package,you are allowed to use anything you get from it.
Flying Knives- Throwing knives only,simple. No perks or killstreaks.
If I think of some more,I'll add them to the list,but at the moment,I can't think of anything!!