does anybody have experience with any VOIP products that are non-standard and therefore harder to block? (Either PC based, WM5 based, or standalone).

I know that some countries, hotels and cruise ships block skype, vonage and other VOIP products. I assume they can only block products based on SIP/H323 with recognizable voip activity. So I wonder which products might exist that use a proprietary protocol, possible based on Port 80 which would not likely be blocked.

I've heard that magicjack (discussed earlier in this forum) is such a product... but I am not 100% sure.... can anybody confirm if it uses non-standard protocols? Or does anybody have any info about this or similar products which are able to get around efforts to block VOIP?