I know this is at the shallow end of the gear gene pool, but was wondering if anyone has any experience with this.
http://www.soundprofessionals.com/cgi-bin/gold/item/SP-PREAMP
No real experience with it, but they've been selling it for a while. My suggestion would be to just save up another hundred or so and look for a modded AD-20 (the mod will supply power to the mics). I ran one for almost a year and I loved it.