Isn't there a dual sim card holder? I'm not sure if there is one available for the BlackBerry or not or if your phone would work with 2 different carrier's sim cards in ath the same time, but it's worth a shot.
Calling plan 59.00 ish (fine with this)
BB Plan 45.00 ish
text messages 4.99 200 text messages
Data overages 1-1,000 dollars
Great....total is 109.99 to 1,108.99
Airmark1 I am not shure what you are talking about, I use the HECK out of my Blackberry Data and even International and I pay my Flat rate of 45 and 20. I have broken the 30MB mark in a month and part of that was international, no crazy fees or "Data overages", just a LONG and heavy bill. Rogers is the only one I know about that hits you up on crazy data overages.