I installed B5 yesterday and my font problem persists. I installed kobo to another box with B4 and worked flawlessly. I guess it has something to do with my X configuration, or maybe ~/.Xdefaults. I have colordepth set to 16, fully changed ~/.Xdefaults.
I managed to kill Kobo Deluxe under B2 a little earlier - installed some of the SDL stuff from the repos. At which point Kobo failed instantly. Couldn't uninstall the packages - Gslapt came up with an error. I've just done a clean install of B2 and its working again. I'll try installing one package at a time and see what kills it.
Maybe it needs a separate build for SOHO. Either that or I need to add something extra to Standard and rebuild it. A bit of a pain...