"It can't be a detachable mag ar even if it is in .22."
Well, sort of. If the weapon is built/modified so that it can fire rimfire ammo only, then yes, it can be semi-auto, detachable magazine, and have a pistol grip. One option for you is to get a 10/22 and get an aftermarket pistol-grip stock, but you're still SOL on getting (legally, at least) any of the 50-round bannanna clips. There's also the "AK-22" and "AR-22" rifles that are occassionally at some shops that I've seen. They're made by ARMSCORE (I think) and look somewhat 'scary', but are still just .22 blowbacks in different clothing.
You cannot get an AR-15, convert it to fire rimfire ammo, and be safe, if there is any reasonable chance that it coud be converted to centerfire. (Reasonable, in this event, meaning that a very competant gunsmith couln't get it converted to centerfire.)
DPMS makes, or at least used to make, a pump-action upper for the AR-15, but this was not allowed because a standard gas-operated upper could be installed in seconds. Presumably, it would be acceptable if you modified the lower and upper receivers so that a normal upper (ie: non-pump) could NEVER work. FWIW, there is little ak-style mutant, that has a pistol grip, detachable magazine, but is manually cycled like a pump-action shotgun. I see them for sale every once in a while as being "CA legal", and would seem to meet the various restrictions and still give you 2/3 of the assualt rifle experience.