fwiw, the spokes are actually quite reliable (giggle all you want about fiberglass spokes, but i don't think i've come across reading about them breaking when i was researching these).
as far as aero is concerned, there make quite a difference
-height of rim
-shape of rim (say the torroid zipp vs a deep V shaped)
-width of rim (if the rim width matches that of the tire, less drag)
-number of spokes, fewer the better
-shape of spoke (which really shouldn't be an issue as most are butted spokes (aka aero) when you go upmarket). well, all except spinergy
here's an old ass post where they conducted windtunnel testing. too bad a lot of wheels aren't tested. one thing that will stand out is that certain low profile clinchers are actually quite aero. HED did their own testing & determined their deep dish to be more aero than that of the competition. take that with however large grain of salt you'd like
http://www.bikeforums.net/showthread...heel+drag+aero
almost forgot, one place you may want to look is the slowtwitch classified section. there are quite a bit of good deals out there if you are patient