Typically the wait time from the Gold Master released to developers and store availability has been around 2 weeks. Apple released the GM on July 1st and everyone is now saying July 14th which goes with the two-week theory. However, 10.7 is not being released on CD/DVD’s it’s a download which means theoretically Apple could offer it on July 4th, but I’d like to say July 7th to coincide with the 7 in 10.7. Companies like to play little number tricks, even google offering a billion PI dollars in its recent participation in the Nortel Patent Auction last week.
Apple shipped a lot of server hardware out to stores a few weeks back, but it was thought it was for the iPad’s being used to display content, which it probably is, but it’s also there to provide downloads of Lion to anyone who comes in to do so. It’s a lot cheaper to push the content to the stores rather than buy large circuits for every store as well. In fact Apple may be demoing a system that might make it into future updates of AirPort Base Stations and TimeCapsules which would store updates closer to you to speed downloads. So 7 days is perfectly good to deploy the image down to all their Apple Stores and test things out in the back rooms of those stores to make sure it’s going to work for the customers when it’s time to come in and upgrade.