If I grab a Telus/Bell/Verizon Storm 9530 and have it unlocked and use a North American SIM card (Rogers/Fido/ATT/T-Mobile/etc.) will I get 3G bands or just GPRS/EDGE?
No, you'll just get EDGE. The Storm doesn't support HSDPA.
Edit: I'll clarify that a little... the 9530 (and the 9500) don't support ATT/T-mobiles north american 3g. It works fine with European 3g networks, just not the particular flavor that the GSM networks use in north america.