Just replace it with something better
The IT group I manage has been using 12" G4 iBooks since last spring, as well as various others that require remote access. They've been virtually trouble-free for us, aside from some bugs in 3rd party software (Cisco VPN client -- cough, yes it's better now). Malware infestations have dropped greatly as a result, since we no longer have Windoze laptops going home to get pummeled and pwn3d, then coming back to the corporate office to spew the crap back out.
We like the size, and the screen is adequate for what we do. More pixels will be welcome, particularly if Apple gets the resolution independent GUI whipped into shape. We're not going to be in the market for these probably til spring 2007 so will have the opportunity to see what shakes out.
I think there is room in the market for both a budget system and an expensive ultra portable in the smaller form factor segment. I know my company wouldn't have bought 12" PBs, they're just too expensive for our usage scenarios (remote network/system administration. We need MS Remote Desktop, VNC, and SSH clients). We don't do Photoshop compositing here.