Good luck on your search for the perfect short---you'll find loads of informed opinions here!

On the sleeveless jersey front, I prefer jerseys that don't have the traditional fitted elastic band at the bottom. So most of my tops are generally fitted through the body, but end in a somewhat relaxed (or at least not tight) hemline. The sleeveless models I reach for most frequently are my Terry Sun Goddess, Terry Singletrack Tank, Shebeest S-Curve sleeveless jerseys, and Terry sleeveless Mandarin. Sheila Moon has some great scoopneck tanks with matching boleros--a combo I love.

The one Castelli jersey I own is very nice fabricwise, but it has the typical tight elastic at the bottom, so it isn't one of my favorites.

I splurged on 3 Etxe Ondo jerseys on Sierra Trading Post a few months back when they were at a 'deep' discount---one is sleeveless. The fabric is absolutely wonderful, but it has the bottom elastic too. I wear it anyway because the feel overall is so nice that I don't mind the fitted band as much as I would on other less well-made jerseys. Ditto the two short-sleeved Etxe Ondo jerseys I have!

Good luck! Be sure to check out all the wares here in the TE store---great stuff and the staff is fabulous about answering questions about fit.