I think mikedavies experience has made him a little pessimistic.
Googling around, I've found plenty of Barton 3200+ CPU on sale, some of them boxed. True, you might get stiffed if you're not careful but there seem to be enough reputable vendors offering them.
Your mobo for the 28000 takes DDRAM and the 1700 may well also, possibly with BIOS upgrade.
Don't give up so easily!