GeneF, I work for the largest steel stud manufacturer in the country. You can use these z-furring strips along your basement walls to insulate the wall. They are available from 1" to 2 1/2" depths to accommodate the styrofoam board. These furring strips are strong enough to support your drywall.
If you want an independent wall (subwall) you can frame it with 1 5/8" studs (or larger)and simply put the board in between the studs. This will save you floor space and with a 1/4" return on the stud, you'll have enough room for an 1 1/2" board. A vapor barrier between the concrete and the studs wouldn't hurt either to keep any condensation away from the steel.
The studs can be installed at 0" from the wall, but again, a vapor barrier would serve you best.
Check out these sites as well www.dietrichindustries.com www.steelframingalliance.com (or is it .org?)