I dunno if anyone posted this before, http://www.hitechcafe.com/eshop/product.asp?dept%5Fid=14&sku=8361%2D100+SERIES has it for $50.
Is it hackable? All I can find is that it has 8 megs of RAM and 1 MB video, but it uses standard simms, IBM's site say that it is upgradable to 32 megs (why not 64 or 128?), and video to 2 mb. There's a PCMCIA slot in the front, and separate mouse and keyboard ports.
Even if it's not hackable, it's still neat to play with for a LAN.