it's the other way around at most places, stand alones sold out but bundles in stock (at least the 4 gig anyway). Looking at my Best Buy district numbers that covers all of utah, idaho, and montana (which is anecdotal as well) only the 250 gig bundle is universally sold out, with the standalones almost all sold out. 4 gig bundles has huge amounts though.
However, from what I hear, the stand alone is about as hard to find at other retailers as the 250 gig.







