I am a sad man who actually planned an OS called CrossPlatform. The idea was a complete VP type OS so you could have Windows, Mac, Amiga and many other platforms on one desktop. Basically I know you could do it with emulators but the idea was to do the multiple pass interpretation like the DEC Alpha and make them all native so you could run them side by side with no performance loss.

Shame I can't code for toffee. It's also not practical but the thought was there. Running something like Wordsworth 6.0 on the same desktop as Maestro from the ST or such just appealed to me. Then again I may just be strange