Oh man, what will Sony do without Open Source?
Seriously, when they had the time and were throwing everything but the kitchen sink into the PS3 (remember PS2 emulation?), it was feasible. The PS3 slim is "What can we cobble together for cheap that does what most people expect a PS3 to do?", and Linux just happens not to be a big sticking point for 99.99% of console gamers. If enough people cared, I'm sure they'd love to support it and take your money.