I have CM10 running off a uSD on my 8GB nook tablet, made with livramax's instructions in:
https://www.mobileread.com/forums/sho...d.php?t=194424.
CM10 is not yet a finished product but it runs well enough. At this stage its still in development so you can expect a few rough edges. Don't sacrifice your CM7 uSD. Save it in case CM10 doesn't work out for you and use another uSD card. (Sandisk 8GB class4 uSD card (recommended) costs $6 on Amazon).