I can't answer your question about the bluetooth handsfree and Torque working at the same time as i haven't got around to trying it yet (if i remember i will try it tomorrow).
As for the bluetooth reader for Android, i bought an Elm 327 from ebay, and it works perfectly with my HTC Desire on 2.2 firmware.
Hope that has helped.

Ive partially answered my own question, just got a standard bluetooth headset connected to my samsung galaxy s, while at the same time streaming music to my bluetooth netbook. thus proving you can have 2 bluetooths connected simultaneously once streaming data and one streaming voice.

I guess i'll take a risk and try ordering an odb bluetooth dongle and see if they both work, i've trawled loads of forums on this and find it odd that nobody ever asked that question before? will post the results for future reference when the dongle turns up 🙂

I can confirm that it does work on mine.

cool, thanks dave

So, what is the limit with Bluetooth? Can I have 10 connections? I have the same worry. I want to build a BT widget, but it has to be solid, always working, never glitchy no matter what.

Is there a limit N ?

My Moto Droid original connects to both my car for voice and the OBD-II dongle at the same time. I was worried about this as well but was impressed that they both worked at the same time. Curious what the limit is for connections.