MacNews.net.tc claims to have prices/specs for an upcoming iMac bump at MWSF, which basically represent iMac speed bumps with a corresponding price drop:
15", 800MHz, $999
17", 867MHz, $1199
17", 867 MHz, $1499
17", 1GHz, $1699
MacNews.net.tc is a relatively new site with an unknown rumor record, and this simply may represent educated speculation. Previously, it is the only site to claim a color iPod II with MPEG-4 Video and Color Screen for MWSF.