Sorry for the suspense. I'm still weighing my options. I might:
A) Decide to build them and sell them myself
B) Work a deal with an existing headphone amp manufacturer to build and sell them
C) Publish it (AudioXpress?) and maybe sell PCB's
I'm leaning towards A) but I'll let you all know in a few more days...
It was one of the most difficult designs I've done... mostly because of the power supplies, not the audio part. It's not easy to design supplies that are very, very efficient, and also sound good (or rather, don't "sound" at all!). Also not a real easy DIY project because of all the SMT stuff on the backside. For those reasons I am a little reluctant to "give it away".
The internal Lithium Ion battery powers it for more than 40 hours at the levels I listen to. I'm not quite sure how much more than 40 hours because I haven't run the battery all the way down yet. Recharge time (uses a 5V wall adapter) takes less than 2 hours.
It measures 106mm long (excluding knob) x 72mm wide x 19mm tall.
It will drive around 8V RMS into higher-Z headphones like the HD600, and ~2.5V RMS into 32 ohms. More than enough to make your ears bleed.
When... If? it is available I would expect a price of around $400.00.