can you use phones made for the US Verizon network (CDMA) work in Thailand? Perhaps with Hutch?

No. Hutch/CAT provide their own phones, and the hardware is linked to your phone number.

I think some Blackberrys may support GSM (as well as CDMA) but not sure about that either.

No, you cannot. I have asked Hutch about this and they explained it pretty well. Hutch has a strange CDMA system. Although they are CDMA phones they use a SIM card because Thais like to choose their numbers. Hutch had to make this accommodation to get customers here. US CDMA phones from Verizon and Sprint cannot accept a sim card so they cannot be used on Hutch's network. Also, the Verizon BBs that use a sim card, the sim card is only for the GSM radio, not the CDMA one, so you cannot use those devices either. You need to buy CDMA phones made specifically for Hutch that accept Hutch's sim cards.

No, you cannot. I have asked Hutch about this and they explained it pretty well. Hutch has a strange CDMA system. Although they are CDMA phones they use a SIM card because Thais like to choose their numbers. Hutch had to make this accommodation to get customers here. US CDMA phones from Verizon and Sprint cannot accept a sim card so they cannot be used on Hutch's network. Also, the Verizon BBs that use a sim card, the sim card is only for the GSM radio, not the CDMA one, so you cannot use those devices either. You need to buy CDMA phones made specifically for Hutch that accept Hutch's sim cards.

Can't you buy a CDMA phone that has a CDMA sim card slot?

No, you cannot. I have asked Hutch about this and they explained it pretty well. Hutch has a strange CDMA system. Although they are CDMA phones they use a SIM card because Thais like to choose their numbers. Hutch had to make this accommodation to get customers here. US CDMA phones from Verizon and Sprint cannot accept a sim card so they cannot be used on Hutch's network. Also, the Verizon BBs that use a sim card, the sim card is only for the GSM radio, not the CDMA one, so you cannot use those devices either. You need to buy CDMA phones made specifically for Hutch that accept Hutch's sim cards.

Can't you buy a CDMA phone that has a CDMA sim card slot?

as a general rule CDMA phones do not have a SIM card. all Verizon and Sprint phones are CDMA and the subscriber info is hardwired into the phone.

In GSM phones the subscriber info is located on the SIM card.

New to the market are some hybrid phones (some announced but not out yet) such as the motorola Droid Pro which will have both a CDMA and GSM Radio. but these are few and far between just now