I've not ridden a bent so I can't comment on loaded stability, but if you're unhappy with bags I'd look at trailers or probably, better still is Mike's suggestion of another bike. I find that with a pair of panniers (supposedly 25 ltr in total, but I'd say a fair bit more) I can carry enough food, wine and beer, catfood, odds and ends for atleast a couple of days. My wife's 3spd has a large wicker basket on the front and a small basket on the rear rack and can carry a similar amount.

Richard