Well, I did the deed. Went into the store and upgraded the other line to the moto x for $1, had the guy activate it and that was it. About an hour and a half later, I called Verizon and we spent about half hour on the phone swapping phones. Moto x is now on my line with its warranty and Gnex is transferred to the just updated line, 2GB data plan and I'm still on unlimited data. No new sims, no fuss, just a half hour conversation with a nice lady telling me about her warm fur coat while waiting for the phones to swap... Purchased my dev edition moto x already... all that's left is to activate it once it's here, then sell off the 16gb moto x as well as this old Droid X that was left behind in the process.
Best part was when they told me the device was $49.99 and the $1 sale was over and I told them well the sign says $1... they had forgotten to take down a sign at a dedicated Moto X display... win.