Id go with a Hammer 7 if you want magfed,alot of players have done similar mods sucessfully,it will give you the option of First strike rounds and theyre inexpensive new
An Automag or Ion are good candidates also.Theyre very modular and can be configured many ways,not too expensive used.With a Mag you wont have to contend with mounting a regulator but its best to have a high output or adjustable regged bottle
Ions can be done a million different ways but you will need a low pressure reg somewhere.Mech Ion kits are very small and can be mounted almost anywhere.SP1 or G1 may be another option if you prefer electro,the firing system is near identical to an Ion but the board and solenoid are seperate unlike the Ions that are one piece.SP1\G1s arent as common used.
Good luck with your build,interested to see what you come up with
ballin' since '95
REAL modders are on M Carter Brown