Why not take out the glass and store it for now? Instead of doing something to cover the glass, you can go to your local Lowe's/Home Depot/whatever, get them to cut you a piece(s) of plywood to fit the frame, put some padding on that, buy whatever kind of pleather you like (padding & pleather should both be available at whatever fabric/craft store you prefer), cover it and then staple it on the bottom which no one will see. Then you just fit in in the frame and you're done.
Kind of like this, but easier because it doesn't have to mount on the wall -
http://www.apartmenttherapy.com/ny/h...adboard-003559