Um, what do you need an rss feed? All you need to do is host the json files on a standard webserver..
Making the json files is somewhat complicated but for just 50 videos it shouldn't take more then a day or two to get the format down and working.. the Direct Player does work well once you figure out the over complicated json files..
I've published here in the forums sample working json files where all you need to do is edit the urls titles and descriptions.
As for the graphics, I used an old version (version 7) of adobe photoshop, you can use any imaging software, make your picture at the highest resolution required or larger, then just simply change the canvas size and save as different name.. in adobe photoshop 7 (written for windows 95a) you simply create a giant picture, select image, then image size and type in the x/y values roku requires and then save the file under a different name..