OK, for starters, it's LTE, not 4G. Everyone has a different name for the next level of cell phone data. Sprint = 4G, VZW = LTE, T-Mo = HSPA+, and i forget what AT&T is calling theirs (WiMax maybe? Bah, I don't pay attention to them lol). Point is, no VZW phone is technically 4G, because they use LTE.
Now, as for any phone being LTE-capable, my guess is no. When cell phone companies roll out new networks, they roll out the network first, and phones second. LTE isn't in enough places to justify them hiding LTE capabilities in the Droid X and Incredible. Besides, having an LTE phone is pointless without LTE. Yeah, they have it in like 9 states (just under 10% of the US). They do NOT want LTE phones out while their LTE coverage map looks like the AT&T map they used in their commercials lol.
Another reason, sales. They are going to keep selling 3G phones until the LTE network is about 60-70% complete. Then they will roll out 1-2 phones until gradually all they will have are LTE phones. This isn't going to happen before January 2011.
Finally, software, no matter how cool (Android lol) it is, it can't give a phone LTE/4G/HSPA+/WiMax capabilities without proper hardware. It can have menus and settings, but it there is nothing for those to turn on/off or adjust, then they are pointless (unless they are teasing us, which cell companies to like to do).
One more thing I was just thinking of. Has anyone heard of the Droid Pro or even the Droid 2 being LTE-capable?? I ask because they are newer than the X and Incredible. Also, why would HTC and Motorola build phones with features that aren't yet available and not market them as "smartphone data future-proof" or something along those lines.
All in all, the LTE phones are not out yet, and no phone sold by VZW are LTE-capable as of yet.