I just returned the mesh jacket I had gotten and exchanged it for one size larger in a slightly different model. I hadn't noticed, but both have waist adjustments. The one I had was just too tight, and in thinking about it, I really don't need the zip-out liner (if it's that chilly, I'll use a different jacket). The one I exhanged it for has a waist adjustment, plus has snaps on the forearms to tighten things there (which I think is good, will keep the elbow armor from sliding around even though the jacket is one size larger).
This is one of the two models with snaps on the arm...this isn't the one I got but almost exactly the same. The one I have is solid black, but has some reflectors built into it, and the sleeve size snaps are on the forearm instead of the biceps.
http://www.cyclegear.com/eng/product/sport_mesh_motorcycle_jacket/web1001097Dave