There are a number of upgrade and aftermarket fences available. Most of the Biesmeier type have a proprietary front rail and do not require a back rail.

Your other option is to find someone who's upgraded their fence and has the old one sitting in the rafters.

Here is a link that might be useful: http://www.rockler.com/product.cfm?page=5933&filter=fence

Biesmeyer or a clone is the closest thing to a universal fence. Table size doesn't really matter. They are rugged and are probably the most used fence in industry. Most of the older style fences did not work well, hence the success of Bies as an after market fence.

Please get a fence that that only uses a front rail. Anything else is junk. If you have novice experience with a tablesaw you can really easily hurt yourself using a poor, or rigged fence.

You can also hurt yourself a lot of other ways using a state of the art fence if you're a novice. Take care and be safe.

Make sure the fence is parallel with the blade. Then move the back of the fence one micron away from the back of the blade. Kickback comes from the rear of the blade binding the material against the fence. Tilt the back of the fence away from parallel with the blade ever so slightly to minimize the kickback risk. You do this by adjusting /shimming the front rail of the fence where it mounts to the table.

"Then move the back of the fence one micron away from the back of the blade. "

And then you will have a problem if you ever place the fence on the other side of the blade.

Leave the blade parallel.

For what it's worth, Forrest (manufacturer of high-end saw blades) does recommend adjusting the fence so it's a bit further from the back of the blade than from the front of it. I think 0.005" is the dimension they suggest.