Dummy 88g tank ?

[mrpain]

I mod'd my MR1 so that I can only use the 88g CO2 tanks and a remote line for anything bigger.

Well after messing with it some I'd like to make or have made a dummy 88g tank so that it has a quick release fitting in the back to use a remote line but keep a tank on the gun to keep its balance....

Anyone ever see this ? Would it also act as a large expansion chamber ?

They are very thick at the butt of them so it should have no probs threading it..