While at Knob Creek last week, I came upon a stange looking MG15 type saddle mag. Closer examination revealed that you turned it over and it took a .308 HK G3/91 type feed tower no less! Cool, HK91 Beta type mag!
Comes with a winder, only $1800!!!!!!!!!
Needless to say, I set it down as soon as he told me the price. Besides, it weighed half a ton empty.  :)

I still want it :) Might have to try doing one myself.