Not on a full sus, but I bent one quite badly on a hardtail. It wasn't carrying very much weight and it still bent. I wouldn't like to use one in the back of beyond unless I had a backup in place.
I'd consider some Carradice Super C Limpet front panniers. The fitting allows them to go on any forks regardless of mounts. They look like they might move around but once they're on they're superb … quickly removed too.
I got one for my commuter bike, a topeak quickrack with matching bag. There's not much seatpost sohwing on my commuter, so the rack is more or less directly beneath my saddle. Althoug it's(very) slightly better now, at first I found it incredibly uncomfortable as my thighs were brushing along either side of the clamp with every pedal stroke
if you do fancy one there was a topeak on in the classifieds yesterday
claimed to carry 7kgs my mate had approx 2 kg on and it snapped in half.
i'd look at something else i.e. epic designs or carousel design works.
either of these would work a treat but not cheap.