The new Inland and Jame River carbines are VERY nice and well-reviewed.
Unfortunately, they'll also run you at least as much as a USGI carbine in decent or better condition will.
Fulton has some really nice examples, too, but they're even more expensive.
Realistically, that leaves AO/Kahr as your only option for a new commercial carbine, at less than $900. With some searching, you can probably find one for $650 or slightly less.
Iver Johnson would be your best bet of the "old school" commercial carbines. Plainsfield seems to have had a decent reputation, too, but I don't hear much about them. Earlier is better (and closer to USGI) with the commercial carbines. Early Universals used a lot of USGI parts, too and were reputed to be pretty good carbines. I would recommend you do some reading, however, if you decide to do the IJ/Plainfield/Universal route, so you know what to look for in these carbines. Do some research as to what USGI carbines are going for in your area. At some point, it's going to make more sense to buy a USGI over an over-priced commercial carbine.