>If you recall, in the first line of G4 towers (350, 400, 450) the baseline tower was based off the old G3 motherboard. Or am I completely insane?

I think you are correct. But, you've got to admit, Apple made the first affordable gigaflop computer before the new millennium!
Here are my honest predictions:
WARNING: This data is not official data, but rather a prediction. Do not assume that the data below are actual facts.
(1) All powermacs will have DDR-RAM running PC2100.
(2) Specs for PowerMac G4 DDR-RAM:
(2a) PowerMac G4 low range: 1000MHz, 60GB, 256MB RAM, CD-RW. $1794.
(2b) PowerMac G4 mid range: 1200MHz, 80GB, 256MB RAM, Superdrive. $2494.
(2c) PowerMac G4 top of the line: Dual 1400MHz, 100GB, 512MB RAM, Superdrive. $3494.
(3) Specs for iMac updates with 15 inch LCD:
(3a) iMac G4 low range: 800MHz G4, 40GB, 256MB RAM, CD-RW. $1394.
(3b) iMac G4 mid range: 900MHz G4, 60GB, 256MB RAM, DVD/CD-RW (Postal). $1594.
(3c) iMac G4 top of the line: 1000MHz G4, 80GB, 512MB, Superdrive. $1894.