I own real steel and don't push my luck but you can pick up one of the old Taso units fairly easily. A machined aluminum unit makes me sweat, I wouldn't touch it.
The laws on such things are scary, according to the men in black suits theres basically no difference between paintball unit and one for steel in this discussion. If you have $200 extra to spend and patience to wait for paperwork it can be done. I seem to recall that there is a clause in there for airguns and paintball guns that if its integrated and cannot be removed with out destroying it then it can be done legally. Look at the Gamo Whisper series and many PCP air rifles. Soldering a can on to a Sheridan should be legal but a removable barrel(ie cocker or spyder) with it built on is not, or so I have read. From what I have seen there is little threat of trouble since I know of no one thats been removed from the general population for it but tread lightly because it is possible.
I have plans for integrating a CF tube over an auto mag that encompasses the body and barrel and as a system it works but its impossible to use as parts.
Everyone says "Well maybe i'll make a difference",
Thinking they've got plenty of time
But you're squeezed a little tighter everyday
Finished before you can commit a crime