That must have been an impressively inaccurate guide to get you into that state!
OK, obvious thing is to try an RUU (though I'm a little disturbed that fastboot isn't getting a response - mind you I've never tried "fastboot devices" when the phone is in RUU mode, so it's possible that's normal). The thing that worries me is that you've changed the CID to T-Mobile, but I'd be very wary of running a T-Mobile RUU because there will be hardware differences between a CDMA M7 and a GSM one. We don't have CDMA over here, so I'm not an expert, but my instinct is that using GSM firmware on a CDMA device would be a very bad move.
VZW RUUs are not easy to find, but there's an XDA thread
here where someone has managed to construct one. There's also another thread
here where someone has collected Verizon firmware (in post 2) as well as a stock ROM. If you can get it into the bootloader normally then the rest should be straightforward, so I'd think that a firmware flash should get you to that point even if the ROM is trashed.
The CID could be a problem though. Have you tried "fastboot oem writecid 11111111" in your current state, to see whether you can set superCID? If the CID blocks things I'd guess it's safer to change the CID/MID in a VZW firmware zip than to try flashing a T-Mobile RUU. Post 1 of
this thread describes how to do that (it's a long post, but it is in there somewhere!), but as that thread is for GSM firmware you should not use any firmware from that thread, but if necessary apply the method to a VZW firmware zip. Editing the zip will break the signature verification, but since you are S-Off that's OK.
Sorry, I have to go offline now, but that's the best I can suggest. An element of educated guesswork, as I've never had the misfortune to get into this state, but I think should work.
