My shell work isn't the issue. Or rather in isolation it's not. I'll run upwards of 40-50 shell sessions (on multiple hosts, with screen sessions on many of them). The net state of all of those sessions, including spatial relations between shells and color coordination (helpful for state recognition) is the hard thing to replace. Note: it's not that I carefully choose the colors of all shells, but I do have a couple of scripts that will kick out terminals in either lighter or darker shades (lighter == remote terminals, darker == local) to indicate stuff whose state I want to specifically register.

Full desktop sessions and browser state are the big ones.

I might be able to look at NX or another remote desktop solution, but those would be at best poor substitutes.