I'm certainly no expert (that should be obvious), but...
My S80 runs Windows CE underneath which is what the 'unlock' exposes.
According to this thread:
[Please Register or Login to download file] MY30 can be unlocked too, and it runs Windows CE also (*assuming* the MY55 also runs CE.
Copying the SmartST software and getting it working on another device is a whole other issue - it might be possible, but dunno...would be extremely surprised if it was legal though. Why not just buy the device you want instead?
BTW for anyone else who lands on this thread, I ended up installing MioPocket which works as advertised: install to SD card, boot and you're unlocked, and looking at a Windows CE interface. Power down, remove the card, and you're back to the original setup running SmartST. Only hitch was that there is no selection for S80 but I chose S90 and it all seems to work. I haven't played with it a lot though...
Info here:
[Please Register or Login to download file] Cheers - Andrew