Hi James!
It would make more sense to make a digital player with a built-in DAC, a combination of BDP and BDA in a single chassis. Consumers who need only a DAC, even if they'll be a minority, will still opt for a BDA but consumers who want a streamer certainly WOULD prefer a single unit rather than two. This new product would outsell the current BDP, I am certain of that.
That said, keep in mind you'd be entering a hot marketplace. From a consumer standpoint, the choics are vast and it is almost impossible to make "the best" one.
Of all the products I'd like to see (a headphone amplifier ina BDP-Pie form-factor), for me, this would not be one of those products.
Hopw this is useful.
Cheers,
Antun