Besides, this thread was made in 2008 so I seriously doubt the original poster is still around. Your best bet is perhaps looking on BlueLaguna.net.
Find the game, burn it to disc, and rip as if it’s a normal audio-CD…. That should do the trick. As far as I know most mega-CD games work as normal audio discs when putted in a stereo.
EDIT
I ripped The Terminator and Batman Returns this way.
A bit of trivia: Shadowrun for SegaCD was the very last game released on that platform.