I have a set of the V style of rods http://www.discountcutlery.net/en-us/dept_22068.html
I bought them from woodcraft but they don't seem to do them anymore. They look very heath robinson but were cheap at the time. I realise that they are not the steel style you refer to, but thought I would mention they are a very good method of getting an edge without excessive material removal. They work in the same way as a steel except you control the angle to the rod much more accurately than freehanding with a steel because you hold the blade vertical and stroke down alternating on each rod.
I would certainly consider a ceramic steel over a diamond one, I think the diamond definately works no doubt, but at a greater rate of metal loss. A couple of strokes before use and away you go.
I have been using one I got at the Good Food Show about 15 years ago ever since, excellent and I am only just getting to the stage of doing something a bit more to any of my knives. I used to get them ground about every 5 years...