I'm wondering what the physically smallest microcontrollers are, that aren't too crazy to program and that are amenable to hand soldering with normal SMT tools. I've found some of the ATtiny parts in 2x2mm packages. Is there anything else like that, preferably with a bit more code space and ram (these things have 512B code, 32B ram)? Is it difficult to work with those packages? A little larger is ok. The AVR instruction set is fairly nice. I'd consider the PIC10's to be crazy to program.
I keep seeing claim that ARM devices are going to replace 8-bitters, but it seems to me that there will always be a need for really small stuff.