Ace,
Singer still makes the treadle base and machine for third world countries.
If you go to a Singer store and the rep really knows what he's doing, after he tells you that Singer has no treadles available (and he means made for US consumption), ask him about the exportation models they have for third world countries ... where electricity is often a monied privilege.
Again, if he really know his stuff, he can get a base for you. And as far as I know, it is basically the same base cabinet and same treadle machine ... even down to those beautiful cast iron legs ...
I have a circa 1916 Singer .... where the electric motor was an option, and the big heavy flywheel is still there for treadle and hand work. The motor screws on the back and has a hand operated clutch that engages the motor ( or disengages it to work the treadle...)
P.S. I have never used this machine on leather. I have always wondered just how thick a leather and how big a thread I could use on this fine antique without possibility of damage. If anyone has experience on this machine, please PM or email me (My email is on my profile).
Thanks!