A full-auto MAC-10 customized by Len Savage is up for bid on Gunbroker here. It includes a "Helmke Special Capacity Magazine" for Glocks as first featured here on Sipsey Street. Here is the description from GunBroker:
THIS IS A FULL AUTO MAC 10 THAT HAS BEEN CUSTOMIZED BY HISTORIC ARMS LLC TO ACCEPT GLOCK MAGS IN 9MM, THIS IS ONE OF A KIND TOY, COMES WITH 2 32 ROUND GLOCK MAGS AND ONE 100 ROUND BETA MAG. THE MACHING GUN HAS FOLDING STOCK, AND 10.5 INCH BARREL THREADED TO ACCEPT M16 FLASH HIDER, ALSO COMES WITH ULTIMA SUPPRESSOR BY COASTAL GUN CO. IF YOU HAVE A MAC 10 AND WOULD LIKE TO HAVE YOUR GUN CUSTOMIZED PLEASE CALL LEN SAVAGE AT 1-706-675-0818.
Pictures up close and personal of Len's work. I have some videos of this ripstick in action, but I have to figure out how to upload to YouTube. Any volunteers? (And yes, Len has an ATF letter permitting this sort of modification since the transferable serial-numbered receiver remains intact.)