Amp'd won't do it...
However people have had success calling and requesting activation of an already owned compatible phone... (you just have to demean your 6600 and call it a razr or something, and they'll say, "Ok." and activate the ESN...
At least... that's what I was getting off the Amp'd forums...
They do use Verizon (kinda like Helio uses Sprint) as a backend.
So... in theory it's possible...
I just started researching it today...
The only thing that looks like it might be a problem is the data stuff...
It'll do txt and phone stuff, but the data doesn't seem to want to connect.
The only problem I have with this is that the user name and password are the same for tethering the... whatever phone they said that you still use ##########@vzw.net and the password is still vzn for the amp'd network. (also works with ##########@vzw3g.net apparently)
So... in my head... the theory works out to, "If you convince them you have a razr (you get $10 off the monthly plan if you have a razr because it doesn't have the push-to-talk feature, they give you a $10 break on the $150 unlimited EVERYTHING plan) and convince them to activate the phone (may take a few phone calls, but really... wouldn't it be worth it?), the data should work just like normal...
But would be a LOT cheaper than the $450 bill I had last month <_<
All I have to go by is someone that mentioned they had an unlocked 6700 that they managed to get activated on the amp'd network.
All the info I have came from Howardforums....
http://www.howardforums.com/forumdisplay.php?f=313