Is it possible to use AT&T 3G on a Verizon LTE iPad?

According to the new iPad tech specs page, in addition to their separate LTE bands, both the Verizon and AT&T models ship with:

• UMTS/HSPA/HSPA+/DC-HSDPA (850, 900, 1900, 2100 MHz);
• GSM/EDGE (850, 900, 1800, 1900 MHz)

So it's clear that the Verizon LTE iPad has the radios and the bands to use AT&T's 3G network. It even has a micro-SIM tray. Would it be possible to get an AT&T micro-SIM and use AT&T 3G on a Verizon LTE iPad?

For me, this would be the best of both worlds. I don't live in an area with LTE yet, but given the rollout pace from Verizon and AT&T it's very likely that Verizon will get to my area long before AT&T will. However, currently, I get pretty good AT&T 3G coverage on my iPhone, and it's significantly faster than Verizon's network. So my idea is to get the Verizon iPad but use the AT&T 3G if I can, until I get Verizon LTE coverage in my area (or I visit an area with Verizon LTE).

Would this work?

Turns out I wasn't the only person that's been interested in this. There's an article on MacRumors that states that this is indeed possible, which is good news for me. The person that discovered it wrote:

Big question on everyone's mind buying the Verizon iPad was whether data from AT&Ts 3G network would work on this iPad, or if Verizon/Apple would block this.

I was one of the first to obtain a Verizon iPad and can happily confirm that this is allowed! I used my ATT iPhone 4S sim card and took out the Verizon sim, and data worked! You must apply the AT&T APN carrier settings before this works though.

BTW APN carrier settings can be changed here: unlockit.co.nz

edit: I just tested this and it works. Changed the APN, put my iPhone SIM in, and it worked.