Grant posted some pics of the latest version of Mark's hub area rack. It looks nice and will fit bikes with mid fork rack mounts.It has tab welded on the front corner that looks like it could attach to the front holes on the Mark's rack or a Mini Campee rack with a Nitto brace rod for more stiffness.
http://rivbike.tumblr.com/
I'm thinking that you will need to have some adjustment on your panniers to fit both clamps as the two top attachment points look fairly close.
Anyway, it looks very nicely designed and it will be well made form Nitto. I'm anxious to get one.
~mike