Just to put a bow on things...
I went to Verizon again for another set of answers (third times a charm) and got some interesting advice today.
The Blackberry is designed differently than any other phone. And even different than any other data ready phone. The blackberry world phone will work all over the world and will pick up signal anywhere. You are however not protected by your "unlimited" plan when you are away from your area. So it is true, you will get charged a ton when you use your data feature when you travel. Also, a blackberry will pick up even when it is turned off. So you do have to pull the battery. BUT, the second you try to put in the battery out of your area, you're stuck. It ALL hits and you're charged for all of it.
They recomended that you connect an old phone that has phone capability and no data capability while you travel so you will get your calls regularly, but charged roaming. With Verizon, there is no charge if you don't pick up, no extra charge for the time that they are calling you and talking to your voicemail. You are charged for the time that it takes you to check voicemail however. It's a regular call of course.
So, the sim card stuff - according to them, you can't unlock a verizon phone and use a sim card from another carrier. They are really tight on the security of their equipment, they said. And they said there is an International charge for texts too.