Hi,
I am also a toy industry veteran. I've 12 years under my belt with a toy invention group, we have product currently with Hasbro, Fisher Price, and Spinmaster to name a few. We were using outside vendors to do custom programming that those vendors did on Sonix chips, then we slowly switched to doing nearly exclusive development in house using Arduino, with Adafruit's WaveShield for sound.
That lasted for about 2 - 3 years, we've since switched to a competitor to Sonix for pretty much all of our electronic prototypes, mainly because like your chip, the audio is built into the microprocessor, but even more importantly to us, the their offerings include multichannel sound, up to 8 channels simultaneously.
Are you planning on offering a multichannel option some time soon? It's the only thing that would keep us from using your chips. Even just 2 channels would be a huge improvement, especially when developing toys and games, it's just too much time to have to mix sounds together and concatenate mixed segments for a single audio channel versus being able to mix sound during runtime and not having to deal with that and all the extra programming that goes with it.
Anyway, I think if you did that, it would be a HUGE point of difference to the Arduino crowd. I realize that I may not be the target user for Foxonix, but hey, it can't hurt to ask. We were looking at Sonix's development system directly, but then came across your system.