Does this mean I could by the HTC TouchPro 2 and put my BB Storm SIM card in it and the HTC will ring and work under my number?
The SIM card has nothing to do with keeping your number and activating the HTC TouchPro 2. As the poster mentioned above, VZW uses SIM cards to allow you to access foreign GSM networks. VZW doesn't store your mobile number or your personal contacts on the SIM card as GSM carriers like AT&T do.
So yes, you can activate the HTC phone and keep the same mobile number. Just keep the SIM card in the Storm in case you ever want to use it again or resell it.