What should work and should not and why (I work on the network)
Ok, I am an engineer working on VZW's network, as well as in the past worked on GSM stuff as well. The reason that VZW could not do voice and data at the same time is because CDMA voice, 1xRTT data, 2G voice, 3G voice, EVDO REV0 and REVA all use the same channel groupes. VZW uses channels 283, 242, 201, 160, 78, 37, and 1019 in the 800 A Band, and with Alltel Acquisition now has 466, 548, 589, and so fourth, the PCS spectrum is abundant too. The LTE is on 700 mhz so uses a different set of radios so could in theory run it at the same time as voice since it would use the other radios to do it. Thats the reason it can work but if they write the software to do it is another thing. They might not because of battery life, would be like running 2 phones off the same battery at the same time. The iPhone will not do it because it will not be LTE ;)
VX6600>VX6700>VX6800 DCD 3.0.0/3.55.04>
TP2 (stock, not inspired to mess with it)>
HTC Incredible, ROOTED BABY!
THUNDERBOLT, ROOTED ALSO!