I know each bike is different, but I have a front rack with a shelf, and don't bother with low rider front panniers when I tour. The front shelf holds my tent, and provides a nice balance to put some weight forward along with the front handlebar bag. Before I bought my front rack, I also considered a rear rack mounted at the front, but the awkward angle of the shelf put me off.
Anyway, I'd guess that had I somehow managed to finagle a rear rack on the front, the geometry would have been similar to what I currently have. However, stability and balance have been excellent and -as I tend to do small mini tours due to my life situation -I don't need to have extra carrying capacity. Were I to do a big tour that required front panniers I'm sure I'd go with low riders, but for the time being at least my setup really suits me.
I suppose what I'm trying to say is that rear racks on the front may be a good idea -much must depend on your bike and what you decide to carry -I guess it's a try it yourself and see what you think kind of thing.
Originally Posted by fuzz2050
it's possible to do, but it requires a lot of drilling and bending. The end result is a really shaky, unstable bike. It's nice to have a platform for a small handlebar bag, but high weight in the front plays poorly with the geometry of most bikes.