Over the course of the weekend I burned a set of WaveROMs with rather generic waveforms, plugged them into the DW, and - we have sound.
http://www.filehosting.at/file/details/744100/WaveTest.mp3

That sounded promising enough to convert some other waves into an appropriate format - Some of you might recognize the wave names from $somewhere:

...this would not have been possible without the excellent information found here
http://www.buchty.net/ensoniq/

And now - let's go find a useful EPROM :)