Well, yes, exporting to mp3 would probably be the easiest way for people using soundfonts. While it is bigger, it DOES allow you to have lots of freedom with what you do (cutting and editing audio, adding reverb, delays, and various effects) You could also try encoding it as an mp3 first, then using something like dBpowerAMP to encode it into an Ogg Vorbis file, which, if done at the right rate, can be merely 8-10+ the size of a MIDI, while retaining decent mp3 data.
As for an alternative, I'm not 100% sure, but I would reckon, you could have your music along with soundfonts in the same folder, and set it up somehow (Again, I'm the wrong person for this technical stuff) so that it loads the soundfonts externally.
In any case, it's very nice anyways. We unfortunately have so few musicians here... some of the best ones are gone as well (tssf), but oh well.