well, using imperial transports with their standard profile as captured transports is okay, thats how me and my friends do it.
but if you want to put some more effort into it, you could build your own orky transports, mabe with normal transport profile, but 6+prow/4+ armour or something, and the strength two transport guns could be orkified as d3 gunz battery, and there you go
![Wink ;)](http://www.specialist-arms.com/forum/Smileys/default/wink.gif)