I got into the ATM schtick around Y2K and built a 12". Thought about motorising it with scrounged stepping motors from old printers, but the gearing defeated me.
Once saw in a mag a twin 17" Cassegrain someone had built because he had dodgy eyes. That would be wonderful to have. Along with the crane & pickup to take it to a dark-sky site.
My Dob hasn't been used for years due to light pollution. It's just an ornament these days.