if you dig around in the archives at  
http://www.emu.com   you'll find the latest OS...  plus if you poke around the store, you'll find that they have old EPS and ASR-10 sample disks/Cd Roms on clearance...
as for you question about the ASR-X and the ASR-10, the ASR-10 can't read ASR-X files.  I don't even know for sure if the ASR-x can read ASR-10 files.