The DAC+ Pro can be modded to allow for external PS for the analog side,though that's a DIY deal,but supposedly it's not that hard to do.
Also consider that with the current 2 seperate DACs you have twice as many chances for noise to creep into the signal chain(s) vs. just one.
Some folks just prefer to have the source & DAC as close to each other as possible and get the D>A conversion over & done & then use analog IC's to the preamp/amp.
For me it was more an idea to simplify the overall signal chain somewhat and reduce the number of D>A conversions and such.
But that leads to other questions,like is all this gear located in close proximity to each other -or- is it all spread out a bit ?
Might help us to really understand how all this is being used,pics may be an idea as well.
HTH
Bret P.