i think the only difficult part is going to be the screen extension, but thats just not impossible by any means. I've never seen a mineral oil mac although it has crossed my mind several times to do one myself. I can't wait to see yours!

On a side note I sold my G5 iMac because the thing ran ridiculously hot all the time. The iMacs were/are great machines, but the G5 models were not equipped to handle the heat.