There is a seller on eBay with a bunch of used rip fence extrusions for sale. As you may know this is the same extrusion (clever, Ryobi) as used in the miter fence, but longer.

https://www.sawdustzone.org/forum/di...-cheap-on-ebay

If you want to upgrade your miter fence from 14" to 23" for better support of miter cuts, here's an opportunity for $19 shipped cost. I'm sure he has a limited stock of them.

I ordered one, coming on the 21st.