Not quite true. I have used an unlocked GSM-only phone on Bell's network without any problems. Put my SIM in and it works. Bell and Telus both run quad-band GSM in addition to their HSPA and CDMA networks in most areas.
Well, either that's new or your are roaming on another network They definitely don't have GSM here.
Both Bell and Rogers offer the same iPad plans that you can subscribe directly on the device. Bell didn't allow that at first but they do now, TELUS still does not, you have to call them.
I highly doubt that they will refuse to take your money for a plan, if unsure ask at the store where you will get the micro-sim card or else you can get a prepaid credit card almost everywhere these days.
Other than that, maybe check coverage maps just in case to see if you have 3G coverage where you will be going. Rogers does not have 3G everywhere and it can fallback to EDGE, Bell and TELUS on the other have only HSPA and CDMA, but no GSM network.
The first sign of maturity is the discovery that the volume knob also turns to the left.
