I've rigged up one of these out of parts and pieces of all the automotive & motorcycle bearing press kits I have. I can press out the bearings on the "do not disassemble" cups no problem. The basic Enduro sealed bearing replacement kit for external BB's is only $13.44 shipped. That's way cheaper than any square-taper cartridge BB you can buy.

I like the idea of just replacing the BEARINGS instead of a bunch of extra metal parts that are just wasted when a BB needs service.