<<For instance, if I could find someone with a 8500/120 who is upgrading to a 150Mhz processor, I could buy their 604/120 card from them and simply put in my machine and restart...bingo all the power would be there. The ROMs are slightly different, basically differentiating the model for "About this Macintosh".>>
Not anymore. The Mac OS doesn't differentiate the Macs anymore. I really liked it when my old Mac said "Macintosh IIsi", instead of just "Macintosh".
On a different note, I found out that the 7200 has a custom video acceleration chip right on the motherboard. At least that's what a web site had written down. This explains the different extensions in the System Folder (there's an extension called "7200 Graphics Acceleration").
