Porting an application to a platform you never worked on is fun. After checking the RKRM and the sources of the v2600 emulator, I managed write an AmigaOS port of Sarien, and it kind of works. It's slow as hell, but good enough for my first attempt to write code on the Amiga :) DICE C seems to work fine.
My dual-head setup with my old CRT and my new TFT monitors was highly unstable with the Mach64 and G400 cards, and it seems that mga_hal was causing the problem. KDE 2.2 works nicely with the dual-screen layout, and so does XScreensaver. Hmm, I wish I had a way to tell XScreensaver to run GL hacks only on the accelerated head.