There are some temporary solutions to multitouch as far as that goes (again see preenv)

As for hardware limitations this is inaccurate to some extent, remember that even the early gen touches are still running fine on hardware very similar to our own, not only that but rumour had it back then that the hardware was also downclocked/limited? the n900 runs under full power, and i'd also say that the majority of users running 800 plus overclocks are slightly, large hehe

resolution scaling i doubt will be needed,just stretch to fit with its ratio to avoid the n900 rendering more then it needs too, the ipad does it fine, but stretched due to the 10 inch wopper it handles.

So again i'm seing no issues and while you have valid points i'm doubtful of them affecting the process too much, technology hasn't moved too much in 2 years tbh, just the samsung galaxy having like half the power of the ps3 or something i read haha.