A few more thoughts....
Dual-Mono: For those that have done circuit designs do understand that matching the trace length is important for critical analog signals and source synchronous digital signals. A common rule of thumb is that a trace of six inches in length delays a signal by a nanosecond (for kHz-mHz), and just four 90 degree turns will also add one nanosecond of delay. Poor board designs can skew the two channels that can essentially have the same impact as jitter. So a dual mono design reduces the complexity of the board design and since you have two identical, smaller boards, with matching trace lengths. Dual-mono design is not rocket science here, and it could even lower the overall costs. You can still do a proper balanced layout for any design, but there's always a tradeoff.
As for the balanced vs unbalanced, it's just an improvement of the noise floor. Using a differential signal in the entire chain from the source to the amplification seems like the best route. Is one leg more important than the other?
Volume control.. During my demo of the BP26 it was less than useful and tried balanced and unbalanced connections along with flipping from 1v to 2v, the volume control never did more than a quarter turn. The lack HT pass-through and source selection is also disappointing. Once dialed in correctly, the BP26 is clearly a preamp worth twice it's price in sound, but damn that remote and volume knobs are annoying. Since the BDP doesn't do auto volume leveling, the remote is never far from my hand when a song ends.
As for integrating a DAC, I'm guessing we will be swapping between various DACs over the years as designs improve. As I don't mind having an integrated DAC, like I don't mind having a phono preamp integrated, it will only be for convenience. Emotiva's XDA digital pre-amp turned a lot of heads when it was released as it was definitely an intersting idea. A digital pre-amp seems more like a marketing trend and might be that next debate like tube vs solid state, cd vs vinyl....