Can't really help you myself, not into mechs and haven't bought stuff for a while. I know a lot of vendors have closed down, and now most deliveries require a signature. Hopefully someone who is into mechs will join this thread.
Have you checked the classified section? Mechs show up there sometimes, or you could post a wanted request. Although if you are a collector maybe you wouldn't be interested in used items.
If you haven't been following the news lately the new postal regs could stop all mail order of vape gear at any time.
good luck.