The good thing is that big people generally require thinner insulation, but that's more than made up by the need to wrap a bigger body.
Short answer, yes.
Probably the best way is to minimize layers. A poncho tarp should fit you while hiking and sleeping, and even a slightly bigger custom poncho tarp isn't going to weigh much. That may not be fun in wet weather though, and probably a bad idea when it's snowing. I'd want a tarp dodger in that weather or a different type of shelter. A wearable quilt would take be wider than for most people, but it'd save weight by serving as your down jacket.
You might need a wider pad. That's going to push 20 ounces in the winter.
I bet you could go under 15 pounds in the winter in cooler months.