Scott, I think there are some sources for reperfed regular 8mm film (maybe Pro8mm.com), but the K40 that John Schwind sells in DS8 and R8 at International Film is recently manufactured and perfed by Kodak.
John had to put in a large special order to get it. Also, he sells Cine-X 50 which is Kodak Plus-X, also manufactured and perfed by Kodak. Actually, I think it is now Cine-X 100, which is the Kodak 7265 stock. But you can still shoot it at 50 ASA and process it yourself in D-94 / R-9 process. That is what I do. If you go with a black and white cine lab for processing they'll typically use D-94A / R-10 process, so you'll need to expose at 100 ASA.
Fomapan R100 in DS8 and R8 is sold by John Schwind and by JandCPhoto, although they both seem to be occasionally out of whichever stock I happen to want to buy.
But you are right, Regular 8mm is not dead, and neither is DS8. For that matter, Super 8 isn't dead even without K40. I can't wait to try out the EPY 64T stock (Kodak gave it stock number 7280) when it comes out.