Decent Quality:
Choate - Readily available
B&C - Readily available

Better Quality:
Stockade - Order/wait

Best Quality:
McMillan - Order/wait
Manners - Order/wait

There are a few chasis systems (XLR??) out now too but I don't have any background on those. If you have the bucks, I'm sure they are quality setups as well. Just make sure if you want the best accuracy out of your gun/stock that you buy some Devcon from Enco and bed your action in whatever stock you go with. Even skim bed if they have some kind of v-block or other mounting block.

Cheers,
Hawk