I'm delighted to say that Synthfont 1.340 works flawlessly in Ubuntu 9.10 using WINE 1.2.x (latest)... I've had no problems at all except the WAV to WMA conversion warning (which I'm not worried about as I don't use WMA files...)
I've successfully loaded up a 16 instrument orchestration, using a 144MB soundfont and played back an 8 minute piece without a stumble or glitch of any kind. I then rendered the .wav file to disk and tested it in playback using the Exaile application. Perfect!
I don't remember if I already reported it, but SynthFont works flawlessly on Mac OS X 10.5 and 10.6 using WINE as well. Tested in the very same conditions as Cymbalom (150 MB SoundFont, multi-channel files, several minutes length, direct rendering to WAV file).
SynthFont works much better than SynFon(One) or VSTSynthFont as it loads all necessary samples and instruments in memory when opening the MIDI file, and not when a Program Change event raises.