why dont you guys head over to http://racegun.dk
They've managed to design a boxless conversion that uses one pneumatic solenoid for cocking, and an electroram (such as the ones used in the E-Mag and EM1) in the grip frame.
They've built 9 so far, and are shipping kits in Mid-June for $495...yes you read right $495 !!!
After much consulting with the guys at racegun, they've also come up with an electronic eye to go with the trigger to be released in a few months for an extra $95. The nice thing is about it, is that even if the eye is dirty or clogged with paint, the marker will default to 10 bps firing rate. They also claim fire rates up to 16 bps with lightened cocking systems.