I'll start with an app called ScaleResolution. I think I found it on Insainlymac's forums but its not showing up in a search right now.
The simple app lets you pick between 80% scale and standard 100% scale graphics.

Programs that are too big to work on the Mini's screen at 100% scale,

can be shrunk to usable 80% scale.

After you click the scale you want, every app started from that point forward is displayed at that scale. If you click 80% and reboot, everything including finder and the dock will be at 80%. Its obviously hacked together, but I've been using it with no problems.
Again, I can't remember where I found the app so I'll host it here, but all the credit is due to the program's author.
http://hcfolds.com/imagehost/ScaleResolution.zip
Thanks
Cal