I don't have any insider info, but after being in the same situation and looking everywhere for Rem #10 caps and coming up empty handed, I'm pretty sure they froze their cap production after the restructuring. If you're desperate to get some and aren't concerned about cost, there are some available second hand on Gunbroker... but that's the only place I can think of.
I have since moved on to CCI #11 caps, which when paired with SlixShot nipples work perfectly fine. I was very pleased with them, no cap jams or failed ignition after 50 rounds in my Pietta 1851 Navy.