I did gridlock not so long back (in fact going back to him soon as it still is not finished) and I have always planned to make ravage as he was the base for the name of mine and my old flat mates website website ( www.ravage3d.com
but I had the toy in hand which was better than any ref. Got any transformers get them out and use them or try and get a cheap one of ebay. Also look at the modern comics as the detail the artiest go to to make the old guys look cool was amazing. (shame Micheal bay could not do the same - fool)
But plz man do someone else than prime - I`m sick of the sight of him in 3d threads (go to cg-talk and you`ll find at least 8 different threads at the mo.) and I`m betting that it gets worse after the movie drops.
There were so many cool robots like
or better still invent your own
All my images are in HD - Plz right click and view image.
3D Molder at AO.com.