Thanks for the input, all. I'll put up some pictures tomorrow to show what I'm talking about, but it's some serious, serious overlap. I may have to go with the Jannd Expedition someone mentioned or just stick with my seatpost mount. Going with the tubus mounting setup will only give me a few inches and that just won't be enough. Also, I don't think the top part of the LG bags can be moved, but I'll see if it's possible to remove them and drill another set of holes. I could mount them more forward and maybe even higher. That might be a plan.

Anyhow, thanks again and will try to post pics tomorrow.