Well MS have started the advertising blitz today, A giant surface advert all over the front and back of the Metro this morning.
With regards to the unavailability of the surface other than from Ms themselves. I've always assumed this is more of a spec tablet rather than the tablet expected to sell the most, rather like the first two Nexus phones that were only available direct from Google.
"Look how cool the Surface is! But don't buy one. Buy this PoS Acer instead please "
How could that fail to work TBH I think the Surface is going to do a lot better than Nexus handsets do. Microsoft have almost made it too good, while Nexus handsets are always crippled in some way (usually storage).