Wow, I am just blown away. You found a really cool loophole in the ork codex. Silly me, I was under the impression that the boys unit had to be 12 or less to take a truck, and re-re-rereading the new codex there is no such restriction. Why did I never notice this before? Must be stuck in an older codex or something...
A great list, I was about to post my list, but after reading your list and seeing trucks I am more distracted than seeing shiney things, and so I must now go back to my list and rewrite it.
One suggestion; instead of a mek, take a pain boy. Put him in with the nobs to make a unit that is really hard to kill off. Used to be that a nob could be upgraded to a pain boy, and it was standard practice to do so. Now that the pain boy is a character you have to add him in. The good news is that you have ten killy nobs, instead of nine, with the pain boy that really does make the unit last a long time.
As for your heavy weapon choice, I suggest maybe taking a rockit launcha per squad. Having a guaranteed hit in the event of tank shock is a good thing. Then, if the offending vehicle is not destroyed/disabled then only a boy dies and not the nob.
A good list all around, and I am insanely jealous that I didn't see the DT loophole before.