Anyone know if there is any difference from BT to BTD?

I noticed them on the "Find a Store" page at Pioneer after setting the product category to Car Navigation.

http://www.pioneerelectronics.com/PUSA/FindStore

It seems there is absolutely no information about either of those models on the internet anywhere, not even pioneer's website. I'm guessing that they are some kind of dealer unit or something, like the AVIC-F7010BT that was made as a unit to be supplied only to auto manufacturers?

That's what I initially thought. When I went forward and actually displayed the dealers it was available from it came up with the 6 Best Buy stores in my area.

Yeah, I saw that too. If it lists Best Buy as a dealer for it, give them a call and see if they know what it's about.