You can also buy a new SAM440.
What is it that windows can do, that you miss in AOS4.x? I use both on my office, and I don't miss anything in AOS4.x, but the SAM does boot into workbench in less than half the time, that my office PC uses to boot into windows.
And on top of that AOS4.x is alot more responsive than windows, not just by margins but by miles.