These are now becoming rare beasts where I live.
I've just had two cases of dead mobos, both fitted with 2 Gb of ddr2, but can't find the mobos to keep the pain down for the customer. ie without having to move up to a ddr3 board (cpu permitting).
I've heard rumours of the Gov (here) imposing import restrictions and that PC components are becoming scarce, but I'm not sure if I buy that. Ok, ddr3 is cheaper now than ddr2, in fact half the price for a 2Gb stick.
Maybe it's just the speed at which tech works and develops.
Frankly, there's more money selling components than a fully kitted PC. I may have to change tactics.