Looking good so far, healthy number of boyz with some well equipped and durable elites to go alongside. Trukk is a great idea, especially with boarding ramps, for getting them in stuck into assault nice and early. (If it doesn't get blown up first)
I'm going to suggest two choices to add to your army, just what I find relatively good.
One is the big mek, either with the
KFF or the Shokk attack gun. The former can support a lot of your army with a healthy save to give it another defence against incoming fire, or make a vehicle he's riding in much more durable. The latter can really spice up the game with a bit of risky, yet potentially devastating power. You could kill yourself, or shoot something with a strength 9 pie plate, or better yet a VORTEX pie plate. Very very snazzy. Overall both choices make for one of my favourite
HQ choices in the whole game! (In my opinion

)
The second choice is nob bikers. Not only are these suitable for any ork army, with twin linked dakkaguns, extreme toughness and giving your army covers saves, but are also handy for your preference of walkers/bikes. I have to say, I completely underestimated them until I learnt the hard way just how AWESOME and orky they are! Highly recommended.
Hope this helps!