Sorry, I don't have a good sliced-salad recipe.
However, a yummy, often-forgotten application for the mandolin is the vegetable tian. It's various vegetables sliced and baked with some fillings or oil or some other binder. It's sort of like a gratin but usually not as starchy or rich.
Below is a link to three recipes of tians on epicurious. I've made the leg of lamb one and it's darned good.
The Martha Stewart website also has fantastic recipes for tians.
And why, oh why, haven't you made homemade potato chips yet?!?! Isn't that the whole reason to buy a mandolin in the first place? :)
Oh and to the Chowhound moderators -- love this new board!
1/2 large head of cabbage,carrots, celery, cucumber, yellow squash, onions, zucchini, radish, red or orange pepper. Use the different blades to make the sliced vegetables attractive; i.e., finely shred the carrot and onion, ripple slice the cucumber, smoothly thinly slice yellow squash., etc.
Top w/ ranch dressing or your own homemade dressing; I can send you a recipe of an oil/vinegar based italian if you like.
This salad is mighty plain sounding, but all tossed together and served w/ a nice artisan bread is VERY satisfying--even more carnivore husband asks for it. 'course, he wants it w/ pork chops.