http://cgi.ebay.com/Biamp-301e-301-3-channel-Mic-line-mixer- audio_W0QQitemZ370022184786QQcmdZViewItemQQptZLH_DefaultDoma in_0
Believe it or not the preamps in these commercial Biamp Advantage mixers are pretty decent. They are a discrete input that Cal Perkins had designed for another product and Biamp adapted for this line. Each channel has a direct out (unbalanced) and the master stage can provide additional gain for a ribbon mic. The master stage also has bass and treble controls as well as an adjustable peak limiter. I used one yesterday on a remote session in order to get more signal from a mic on a mandolin.
This seller has at least 12 of these 301's listed. I think there's also currently a 601 listed that has 6 mic inputs. Anyhow, I don't know how you could get better mic pres for the money. A truly low budget solution.