At high levels there should be Scrolls of Enhance Town that you can read to upgrade the town with a random upgrade, like a new shop, or a street light, or more roads, or a section of wall, or something. If the town ran out of upgrades, then it could just do nothing, but it would be interesting.
Alternatively, there could be Scrolls of Enhance House.
Scrolls of Enchance Town
Scrolls of Enchance Town
In my mind's glaza I viddy yarbles of tolchoking ultra-voilence. - Chuchulain