Assuming that you can get the source to these desktop applications and re-compile them for ARM. I also doubt that older Win32 libraries will be compatible with WinRT.
You would basically be getting WinRT "homebrew" like you do with some consoles, a cool hack but probably miserable for getting work done.
OTOH an ARM based ubuntu might be a usable dev system.
That said, if you want to run desktop-style applications, you're far better off just buying one.