What did I do long term?
To be honest - nothing. At least nothing successfully (yet).
In my case of the wireless card, it does not seem to be the aircard itself, nor its firmware that is causing the issue. It seems to be Cingular's Communication Manager software.
As long as the software is not on the laptop, the i2050 works fine (even with the system recongnizing the sierra aircard and leaving it enabled).
But once the Communication Manager software gets installed - BAM! - i2050 'Forwarding'.
So, I've looked in Windows' Task Manager, as well as Windows' Services Utility, for services running that could be Cingular's, but have not been able to find a service that, when stopped, enables the i2050.
According to Cingular's website, I have the latest version of the Communication Software.
So, there is nothing I personally can do on the laptop at this point. I will be calling Cingular to ask their technical support if they can design a patch that allows their product to work with Nortel's... but do you think that will happen? We'll see...
In the meantime, if you are stuck in a position of supporting the i2050, you can claim that they have to remove their Sprint wireless software; otherwise the i2050 is not compatible/supported.