Yup, I've got a few genga and other art sketches 
framed. It really is not that different than 
cels. Use the same quality materials that you 
would with cels. Just make sure that when you 
tape the genga to the mat, only tape the top two 
corners and try not to use too much tape. Use 
just enough to keep it steady, because you may 
wany to remove it someday and the less tape there 
is, the easier it will be.I've used different 
color mats before, but I find that black is 
usually best to showcase the drawing. I've had 
the sketch framed for over a year now and so far, 
no problems. Good luck.