Emu XL-7 & MP-7 User's Group

Does anyone know if there are any 'generic' Flash SIMMs useable in
E-MU command stations and/or Ultra samplers? Or could anyone tell me
the configuration/spec of the Flash SIMM ROMs that E-MU use? (I
imagine E-MU had someone else manufacture them for E-MU). 
I want to buy an Ultra sampler to write Flash SIMMs for my command
station, but as E-MU no longer stock these, I need to find an
alternative. For example, routers use 16 & 32 Mb Flash SIMMs, has
anyone had any success using these in any E-MU product?
Many Thanks,
David Unlimbo.