New forum type?

At present we have standard forums, and redirects. A useful one (at least imo) would be to add a custom option, where the board admin can insert PHP code. In effect this would create a TR cell as normal, but with a TD of all the cells linked which would then show the custom code (so we have the totla width of the board for whatever but contained in a cell). This custom code could be anything, banner rotation, google ads etc. even some custom pictures.