I went with this recipe. Notes:
-Doubled it, of course. Made for a VERY full crockpot, but fit.
-Used no-salt-added canned tomatoes. I always do. The regular are so high in sodium, and it doesn't change the flavor.
-Used ground lamb, drained after browning.
-Used Italian seasoning instead of oregano because it's mostly oregano and I think I used mine up.
-She didn't say how to slice the eggplant so I quartered it, peeled, then sliced the long way. I sliced the onions in half rounds and then halved again to get quarter rounds. After seeing how much space they took up next time I might dice the onions (if there is a next time-- which there might be, since it smelled delicious.)
-I used green bell pepper since no color was specified. It seemed a bit bitter and with long cooking I didn't want it to get more so so to cut any possible bitterness I added about 1/2 Tbsp. honey.
-I put the Feta (I used reduced-fat tomato and basil, it was on sale and, well, reduced fat, you know I never use full-fat cheese if I can help it) on the top, just crumbled all over. I figured that would let it kind of melt down for a more traditional moussaka topping without going to the work that reviewer did of making a bechamel. I'm not a bechamel-in-the-crockpot kind of girl most of the time. ;)
It will cook about 8 hours on Low.
I am categorizing this under lamb, because that is what I used, but also under beef because it could easily use ground beef instead if you don't have access to/can't afford ground lamb. (She says you can also use turkey, feel free but I'm not going to categorize it under every possible substitution. If I substituted, I would do beef. ;) ) I was surprised to see, though, that ground lamb at Vons was actually not much more than ground beef and was fresh and looked very good.