cmk, congrats on the P5D5. I agree with a lot of your sentiments regarding its dynamics, separation, and air. Question about using PLL2. Arent you slaving your P5 to the D5's clock? If so I would suggest you try this.
arbuckle, you can have multiple digital sources hooked up to the D5, just as long as they have different cable types. There is only 1 set of each type on the D5.
bar81, I personally think the P3D5 is the best combination since you get the better transport of the P3 with the new 32 bit dac of the D5. But as you said, if the P5D5 is close to the P3D3, then perhaps it is a great deal.