I debated on this, but ended up using skirting for mobile homes on our park model. It cost me about $500, which included buying two access panels from a local RV dealership in Brainerd. I went with the vented skirting all around, my neighbor in the campground also has the identical skirting. Used a vinyl cutter for most of it.
Since we also had a deck built, I used 2x2's and lattice around the underside of that. I used aluminum screening and small staples into the back side of the lattice - less bugs can get in and my wife HATES spiders.
Also, the deck is high enough - about 30 inches - that I was able to plan for storage underneath it. I drilled a couple of very small holes in the lattice, two on one end for a set of small piano hinges, and two on the other end for a gate lock like this:
Gate lockIt looks pretty nice, but I went cheap on the lattice as I anticipate frost in the ground and things tend to move around a bit. It can't be "permanent" anyway.
edit: added pics of the front skirting and some of the lattice.
front skirtinglattice on back porch