I regularly cast #6 foam hoppers to smallmouth with an 8.5' 4wt ZXL. No problems at all, and in fact, I use that rod for bead chain Clouser minnows. I use 4X and 3X (mostly 3X) 9' leaders for all of my smallmouth fishing, and the ZXL does well in wind for me. Here are 3 videos using my 4wt ZXL: http://www.youtube.com/my_videos?feature=mhum
I mistakenly say "smallmouth" in the largemouth video, so you'll have to excuse that...
The 5wt ZXL has a lot more casting power than the 4wt, and might be the better all-around rod. The 4wt is what I use 99% of the time, however. The 8.5' 4wt ZXL will cast quite a distance when a double haul is used, and I have no problems with it on the Delaware River. In the smallmouth video above, I was casting a #10 Black Nose Dace at least 45 feet to that fish. The smallmouth were chasing minnows right against that bridge wall (far side). That smallmouth took off downstream at full speed, and created quite a tangle in my reel. I was
able to hand line him in, however, and if you wait until the end of the 1:06 minute video, you can see one of many jumps that fish made. It was very exciting!
I should note that I have a preference for 8.5' rods, and have never tried a 9' ZXL in 4 or 5wt.