I am afraid you are stuck with 800 X 600. That is the physical limit of the display. (number of pixels) You could try replacing the LCD with a higher res one, but I don't know if the rest of the hardware would support higher res... ( I doubt it)

BTW I am running 10.3.9 on my old clamshell 366 with no problems. Not as fast as my G5 iMac running 10.4, but hey it works fine!
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Macbook 2.1 core duo 1gig 160gb sata
iMac g5 w/1 gig 160gig all-in-one and SWEET!
iBook G4 IGhz
Quicksilver Dual 800's
iPod touch
"Guys, I think we just lost the platform here" Pete Conrad
When in doubt, try SCE to AUX