Can you define "absurdly expensive" a little more narrowly? The suggestions above cover a pretty broad range.
KEH shows a fair variety of Leitz lenses in the range from about US$250-500 at the moment. The page of opinions at http://www.cameraquest.com/ltmlens.htm might be useful in narrowing down your search a little.
I've found the Nikkor 50/2 to be excellent in bang-for-the-buck terms, but it's not collapsible and that may put it out of consideration for you.