I have a wolfman Rainier tank bag, and is OK for me. It has a a number of side pockets and clear map pocket which is about A4 size, however maps are rarely A4. I end up folding them in different ways so my immediate route is visible.
This is is not a waterproof bag though, and the cover is very ordinary. Having said that, it's not been a big issue for me and ridden through some decent storms with it.
Wolfman do waterproof one in their expedition line, it does have the map pocket, but no side pockets.
According to their website, they should fit your klr
I'm not fat.. it's a power bulge (allegedly)!