Well, I fired up one of the last remaining PPC boxes I could get my hands on and re-build the project under the old Xcode and for PCC only. The result are a not-as-pretty – but functional – 10.4 PPC build of DBCC Desktop (76KB compressed archive).
I moved the project back over to my Leopard box and compiled it as a Universal with a 10.4 target architecture as well. I did not have time to test the results on Tiger, but it works on Leopard. That one is DBCCDesktop10.4-Universal.zip (76KB compressed archive).
One reason for the failure of the previous 10.4 target was the use of the BWToolkit and HUD window. There were other incompatible project settings as well.
This is probably my last fiddling with a 10.4 compatible build.
If anything, I was able to savor the beauty that is Xcode 3.x having re-lived the horror that was Xcode 2.x. How did we ever build apps? :-)
There was a bug in the threading in version 1.1 (apologies for not posting an RDN-update for 1.1) which is now fixed in version 1.2 (188KB compressed archive). No other functionality changes, just a bug fix.

In response to a comment, I am also releasing a desktop version, conveniently called DBCC Desktop (272KB compressed archive, OS X 10.5 ONLY). It runs dock-less and menu-less, effectively making it a widget for your desktop. Just click the "Clear Cache" button and you'll get your space back. The info button takes you to the DBCC portion of this site. I did not put Sparkle updates in this app, so check back here for updates. NOTE: there is a discrepancy between the sizes reported between the widget and desktop app. I use "du" for the widget and Python modules for the app. I'm working on tracking down why there is such a difference.
As you can see, I take feedback and problem reports pretty seriously, so drop me a note if you have any issues, complaints or feature requests.