I know these are no longer being produced but does anyone have a source? I need both front and rear for 11 inch drums

Some older auto parts stores have old inventory of Dorman nuts and bolts. Not your Autozones or the like. I would call around, maybe NAPA even still has some in their system? Also, many racers switched them out for RH because it was easier to have all the same. Find some old Mopar racers and ask around? You never know. I still have a box with some of that stuff (but no extra LH's) Another option is to look for a car at the local junkyards and get them off of it?

I have a set of good used rears that I'd love to get out of my parts bin

Didn't someone start offering correct repros a few years back? IIRC it was Aloha, and they of course are gone now, but maybe it would be worth checking with the new place that rose from Aloha's ashes, APEX to see what happened with those repro studs.

I should have checked before I posted my previous reply.
http://www.apexautosports.com/store.html