I'm on Digest, so my apologies if this is a duplication.
For the gent looking for a mate to his single brake lever for the path racer: rather than search for an old brake lever to disassemble, or haunting ebay for a Dia Compe stoker stub, why not make something yourself, as I'm sure happened "back in the day" all the time. Start with any brake lever clamp for which you can find a bolt of appropriate thread and length, and then turn down a lovely piece of wood on a lathe to the desired dimension, drill a center hole for the bolt and then spend a little time filing out the back to match the shape of the bar you're mounting it on. A little Danish oil, or maybe shellac if you're Old School, and you've got a handcrafted treasure. So long as you were careful, it ought to be quite serviceable, provided you're not doing bell lap sprints while holding on to the thing. Could be quite lovely if you found a nice chunk of something exotic - think of the patina it would have after a few years.
Cheers -
Derek Vandeberg
Bigfork Montana