You can operate a Shocker fine on an Impulse noid, but they are the exact same size as a Parker.
Is a MAC43 noid a possiblity? Yoda has used them before and PE boards crank out enough jams to power them correctly.
** Actually, from that same thread (http://www.pbnation.com/showthread.php?t=3863864
These solenoids are mentioned to replace an 05/06 Ego. 05/06 Ego solenoids are whats used in Shego mods that remove less material from the frame.