If you want to emulate higher-level play, I think it'd be simple enough to add on some special improvements that unlock after leveling up. In OD&D, the fighter would get men-at-arms and a keep, a wizard a tower or something, and so on.
Using the AW method, it'd be simple to do this with Tony's hack. Just have some improvements you can choose that unlock at certain levels, such as something like:Keep
You can build a keep and attract a company of men-at-arms. Temple
You can build a temple and attract followers and priests. Tower
You can build a mage's tower and perform advanced spellcasting, rituals and item creation. Guild
You can build a hideout and attract a gang of thieves.
And, so on...
Then, just use the Hardholder, Chopper, Savvyhead and Hocus as guidelines for the numbers.
This is pretty much what I did with my reflavoring of AW for the Dark Sun setting