Modern Warfare 2 Class Editor?

Hello Community,
Is it possible to make an Class Editor like thiz one?:
Its about having Weapons in the grenade Slot or an RPG with heartbeat Sensor

Yes. But there's no point to it, the game won't actually give you those guns with weird attachments because the models don't exist in game. If you try to switch to your secondary weapon in game, you'll have no gun. Besides, public matches and dedicated servers were patched to reject such classes, making them unusable in game.