There was a Touring thread not so long ago that discussed, IIRC, using a rear rack on the front.
I am not sure about the low-rider with a shelf. The low-rider is designed specifically to place the panniers low and not comparatively higher up like on the rear racks. As a result, there usually is a hoop that connects the sides to stop them from turning into the front wheel. This is in essence the Blackburn low-rider rack design. The Tubus front racks are somewhat different and don't have the hoop.
Maybe this little rack (
http://cgi.ebay.com.au/ws/eBayISAPI....ayphotohosting} designed for MTBs and currently on Australian eBay might be useful. For less than $30, it's an experiment that wouldn't break the bank. Although, you would likely need mid-fork braze-ons, you still have the issue of panniers mounted higher than on a low-rider system, and you would need to watch the weight you loaded on to it.