Just a brief comment........ You want something smaller and more robust than a laptop to play SMF's? Try a SC880 Pro module or even an older M-GS64 rack module......

As good as the G1000 mp3 (same engine), bombproof, no latency issues (how do you deal with integrating your keyboard and laptop without soundcard delay issues?) and NO CRASHES....... EVER!

And, if you are using the sound-font as SMF playback ONLY, and you aren't using the sounds to play live (latency issues again), why not just record the SMF through the best gear you can beg borrow and steal and then just use MP3s? An iPod would be sufficient, I'd say (and a video one could display lyrics or leadsheets for you, too)

BTW,,,,,,,,,, no, I don't have a life; I have a JOB! It's my job to sound as good as they pay me to sound, and they pay me pretty well! So the several weeks it took to tweak my SMFs and styles from the G1000 over to the G70 was work that I consider I have been paid for. And considering that I used the G1000 for over 6 years as my main gig keyboard, and anticipate that I will get at least that from the G70, a month or so doesn't seem that long for all the use I will get from them.
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An arranger is just a tool. What matters is what you build with it..!