Ok, basic filtering is in the logo site code now. Click one of the filtering links at the bottom, and it happens. It dosen't save this preference though, so once you leave the boot logo section and return, it will reset to showing all.

I'll look into adding the other categories later. That will involve some database hacking. (When I do this, all logos currently approved and set to "Other/Unclassified" will be reset, so I can use the web interface to change them. So keep that in mind if all of a sudden 60 logos disappear in the next few days).