OnStar personal calling does not require you to have verizon, but the minutes are more expensive if you purchase them through OnStar.
You do have to have digital hardware to link to your Verizon account but Directions and Connections is not required, you can use the basic package and still link it to your verizon account for whatever Verizon's add a line fee is.(I think it is 10 bucks)
The '07 SRX has a Gen 7 hardware package so you should be good to go for the Verizon deal, or any feature that OnStar currently offers.
No SRX does not have bluetooth compatibility yet.
Hope this clears up some misconceptions.
For further details on OnStar features check out the OnStar website
www.onstar.com
Frankly, I wouldn't push too hard for bluetooth compatibility yet. I would say within a few years most carmakers will adopt it for hands free calling but right now I see too many "glitches" for it to work smoothly.