I still have a few IIfx terminators.

I think your best bet would be a Macintosh IIx.  Relatively cheap to fill out the RAM, and you can easily upgrade the CPU to a faster 030 or even an 040.  Overall, with upgrades, I think a IIx would be faster and possibly cheaper than a IIfx with a decent amount of RAM.

I've been on the lookout for a long while for a boxed IIx.  It's the only machine that would replace my IIci, and only because it has 6 NuBUS slots (which I would like.)  I'm 1 NuBUS slot short of my ideal setup.  I'd even settle for a boxed II and a IIx motherboard, since that was an upgrade path.