I see no reason USALS can not be implemented on an HH mount like (birdview?) if commercially manufactured for larger dishes, but I suspect the cost of manufacturing these mounts might be problematic and demand low to make this hardware practical. Software to run a linear mount from a controller like the ASC-1 would be interesting though. All those variables would make it difficult to get perfect tracking... but with very careful accurate measuring it should work. It's quite easy to find satellites and record their positions on DISEqC 1.2 once you have found your most south, east, or west sat so not likely a lot of energy being dedicated to implementing the higher level calculations.