Sweet - the Leisure Jacket has arrived. The back is a bit too flexible/soft for my liking. BUT I just discovered that it can be tweaked...
The 'frame' that the 505 sits in is attached to a square of cardboard and glued into the cover. I ripped the 'frame' out of the zippered cover, and with adding a piece of board/plastic in between the 'frame' and the cover, stacking and gluing them back together, I think I will have a nice and rigid back that will protect the screen perfectly. The glue is drying as I write this, so I'll test it tomorrow. And post pictures once I get them transferred to my computer.
Thank you cassidym for letting me have your broken cover, I wouldn't have had the guts to buy one unseen and then tear it up.