Do you actually know this'll work? You couldn't upgrade from 10.4 to 10.6, even if you had a dvd, it required you upgraded to 10.5 then 10.6 (or reformatted your drive and started clean.)
The pricing structure, 30$ for an entire OS, assumes you pay for the OS progression, which i assume is why they don't want people skipping OS releases. This is probably why they avoided a DVD release as well, so people couldn't just reformat and install clean, at least without paying more for the thumb drive.
Personally I wonder how this will affect Hackintoshes, hopefully one will be able to install lion to a hackintosh from thumb drive without too much issue, and i wonder if you have a 10.6 hackintosh if the app store 10.7 bundle would upgrade fine.
I'm very excited But I'm stuck here at some crappy summerhouse without proper internet (using my iPhone 3GS, but that would take 11 hours to DL and i got 1 GB data cap ).