As stated there are plenty of units that have fresh capacities equal to your current rig, but these tend to be the larger heavier units that won't necessarily be able to access the places you are longing to go. Remember you're still driving a large pickup truck with 6000lbs of tall, wide, high-center-of-gravity cargo in it. You're not going to go scrambling up rugged logging trails, fording creeks, etc. with a unit that large.
If your desired destinations require a smaller unit with less capacity, behavior modification may be the only practical answer. I understand it may not be the answer that you want to hear, but you need to weigh out for yourself whether you like those long, hot, luxurious showers at the campground, or being out in the boonies with a priceless view.
My TC has a whopping 18 gallon fresh tank. On my own I can easily stretch it over a week, and really, it's not hard to have a satisfying hot shower on 1.5 gallons of water.