Simplicity parts picked up ... just have to cut the chains and we'll be ready to install:
Cost was higher than I was hoping for, $267.11 to do these four pieces. The cost of the sprockets should have been around $75 or so (impossible to tell for sure from the invoice which is somewhat confused, in terms of breaking out the parts from the labor) ... which means the labor - to turn the old sprockets off and fit the new ones - was around $190.
Overall, I'm pretty happy - I was under the impression that they were just going to machine things to fit and I'd have to weld the sprockets on myself. The new sprockets were welded on when I went to pick them up.
Also the guy knocked a $1.50 off the per foot price he'd previously quoted me for some good US made chain (not Diamond but comparable) and since I was a little short with a 10' length (that's how they sell it) he tossed in 3' of Peer import chain he had in the back, along with 4 master links, for free.
The cost of a single drum/sprocket assembly from the Simplicity dealer was $162.20, and the jackshafts (the ones with 2 sprockets on each shaft) were NLA from Simplicity.
The only thing that remains to be replaced are the large sprockets on the wheels ... and based on how they looked I think I can get away with letting them slide for now.
If I do end up having to replace them, the sprockets should run about $60 each from Yohe (compared to $172 from Simplicity)