No I don't have disk-warrior. I used Leopard Cache cleaner, had to restart ... so that didn't work. Buyed a share-ware-version, but didn't get a serial number to use the virus-checker I have Windows on my HD, I split it up with Bootcamp. But I only have used it once or twice about a year ago. So I haven't open my Window-version for about a year ... Long before my (re)start-up problem started.
I too go along with running something more powerful than Disk Utility, something like DiskWarrior or TechTool Pro. With the stuck files in the Trash it seems you might have some directory damage that Apple's Disk Utility can't fix.
It's a tough call. Can't guarantee DiskWarrior would fix it so spending the money is a gamble, but it is a good tool to have in the tool box.
Maybe an Archive and install preserving user settings would fix it if it's file corruption in the install, but I'd be hesitant to do that if the disk is having directory issues.
Make sure you back your important files up to an external hard drive, or DVDs or something before doing an Archive and Install.
Combo-update ... I tried that ... It hangs during the update ... so doesn't update :-(
You've got some serious disk issues, or serious file corruption in the installed files. You did try repairing permissions in Disk Utility? Some call it a placebo, I've fixed quite a few machines running it though.
Sometimes a machine is hard to fix when you are trying to get it to fix itself. Therefore, I have found that booting it into Firewire target Disk Mode works great since you can then run repairs and utilities from a different Mac.