Sorry I don't have any weights for you, but take a look at trigger spin reels, like the Zebco 11T. It is certainly the most compact 4# reel I've ever used, and it might be cheaper than the really light spinning reels. Some of the reviews on that site are disconcerting, though. I used this reel for at least 10 years with no trouble.
Don't be fooled by "titanium" on a cheap reel-- it's probably just the line guide or a coating on the ball bearings. Sure, it's a nice feature, but it hardly does anything to save weight. Ultralight reels are named so for the type of line they use, not necessarily the weight of the reel itself. If you are dead set on the ultimate lightweight spinning reel, the Shimano Stradic CL4 Microline, made with carbon fiber, might be nice. It's only $200.