I have checked it a few times and used a few for Wii U Aroma RA sets I put together. Many are my own and most are from others I scraped random from the web, Launchbox and EmuMovies have great art as well.
Making for Wii U is much easier since the dimensions are straight forward, just a case of how particular or effort put in to get nice results.
For Wii, it is a different challenge... RA-SS Hexaeco is a little less time consuming but I try to make everything as clean as I can, so those bezel sets to me quite some time, especially the universal console/computer bezels. The SS Arcade bezels set is massive and also took me some time to complete.
The most difficult were Wii RA bezels since the dimensions were unknown until recently
@cheloruiz79 figured out some crucial details. From there, I fine tuned it to the best of my knowledge and current ability, for the longest time I thought Wii RA bezel support was broken.
Since that revelation, I put together a pretty comprehensive set for RA that I use for just about all emulation unless there are speed issues.