I was wondering (I do a lot of that) if the hassle wasn't an issue, would it be better (ie: sharper) to place the filter on the back element of the lens or is it better to put them on the front?

Most LF lens have a threaded rear element so I think this is possible.

I'm being alturistic here, I know it would be a bother to do it, so that is not the issue. I am looking for maximum sharpness, contrast etc. We are assuming we have the best filters money can buy as well.

Has anyone ever tried this?