I have seen teh eze Rv Gutter, and I've even bought a short length of it to install along my rear wall above my tailights, but have not installed it yet.
Essential Products RV & Marine - EZE RV Gutters
Just yesterday, i saw someone post a question about a different one taht I had not heard of. i like the look of it better for the intended purpose as a roofline gutter
https://www.rvupgradestore.com/RainK...elief-p/rk.htm