I got the wheels, hub caps and power cable from here - http://zinge.co.uk Very good coms and super fast delivery.
As for the trolly, I'm going to add handles to the support arms and if I can fit them some tow hooks. I thought about adding a gun shield but decided not to just from shear laziness - I may play around with a little more before rolling out another 17 - yes I'm a sucker for punishment! lol
I say 17 but it depends what list I end up running in 6th ed for my renegades. I might add some chains to the arms too. I'll keep this update with any changes I make.
I went the route of using ork zzap gun chassis for all my heavy weapon teams:
"Gloria Imperator, The Firstborn Stand!" My Non-Red Vostroyan Army! Current Army Picture on page 130-131
Which work a treat!
Found this some weeks ago. Do-it-yourself- Rapiers
I did think about the zap gun chassis but to make so many would have cost a small fortune - still lovely idea and great squad
The rapiers are a good idea as well, nice well made model.