If you have the space and can add 5.1 pass through I would be all over that! Guess that would depend on whether you adapted the volume control of the BP16 or the BP26. Highend stereo preamp with built in VERY flexible dac (assuming that the BDA-1 comes through with full features), multiple remote switchable inputs and analogue 5.1 pass through!
It would perhaps be a niche market, but you would have first mover advantage! I would be more than happy to let my DVD do the movie codec processing. Think SP1.7/2 with the multichannel digital replaced with the BDA-1 and 5.1 passthrough intact. Better yet, allow an upgrade path for current SP1.7/2 owners and you could go a long way towards keeping many current owners happy with an option that may work better for them. Moreover, it could allow an outlet for traded in SP1.7/2 that are moving to the SP3. Take them on trade, retrofit with BDA-1 stereo dac and resell them.
That would eliviate the potential headaches of warranty service on all the 1.7 digital sections out there through 2022 - 2024. Some of the trades could certainly be scavanged for that, but refited units would fall under the 5 year digital plan and future upgrade revenue potential. As a side note all this recycling is very GREEN to boot! Hmmm something to think about......