Junkyard,

Both bikes are using the same frame, I believe. Geometry won't be any different. The big difference between the two is going to be your fork. I can't comment on the pluses and minuses of either Marzocchi, but that's where the real X vs. Y is going to be. You can upgrade your bar cheaply, slightly better cranks probably won't make much difference, and you should be swapping out the stem anyway to dial in your fit. Upgrading a fork can get way pricey---definitely more than $150 if you have to take a loss selling the one that comes on the Cinder Cone. On the other hand, the fork on the Cinder Cone might be just fine for your needs/wants, since it'll be better than the stock fork on the more basic Blast.

See if the shop'll be willing to swap forks. Doubtful, but worth a shot. If not, and if you'd be happy with the fork, take their offer of swapping out various parts. Maybe even get them to throw in cages and a discount on accessories (though many shops will do that anyway).