There's a new NES flashcart being released soon:
http://chipmusic.org/forums/topic/2004/ … a-1-built/

also if you wanted to do Game Boy, you could get an Arduino Boy and run mGB (the gameboy equivalent of using a MidiNES)
http://code.google.com/p/arduinoboy/

here's some other options, though not specifically for your setup:
Family MIDI (I don't know anything about this)
http://chipmusic.org/forums/topic/2016/ … i-updated/
Famitracker: (http://famitracker.shoodot.net/) PC Tracker to write NSF files. You could run this in a dual OS thing on your mac (VM Fusionware, that other one i can't remember the name of) and then play the NSFs back on an NES using a Power Pak (http://www.retrousb.com/product_info.ph … ucts_id=34)
NTRQ + Pulsar (http://blog.ntrq.net/) Tracker programs for the NES, run it on a Power Pak

so i'm new to the forum and chip music in general.  i"ve been using some plugins on ableton live but would really like to use my nes for some music production.  It seems that midi nes is the only solution i can find online.  Am i missing something?  I guess i'll buy that if its  the only solution, but eveyone seems to complain that they take too long to ship and  i cant find it on ebay anywhere.   So any suggestions or help on getting started using my nes would be appreciated.  i run ableton 8 on a mac os X.

thanks for the cool site.