http://alternativeto.net/tag/uninstall-manager/ - filter by OS X.
I've just started trying out Magican; the way everything "just works" even though there's no company info and all the text is in mangled English makes me VERY cautious about this (might want to ensure you've got little snitch installed); it is possible that this software is exfiltrating a bunch of data and is as corrupt as MacKeeper. Great tool for rounding up the sort of info you're looking for though, and has a built-in "malware scanner" (doesn't say which one or how it works) as well as other goodies.
So... be careful how much you let it do, but that thing could definitely help you trim and archive both before and after.
I did some digging, and it looks like Magican is owned and run by Hao Xu -- @windknown, an author of
http://www.computer.org/csdl/proceedings/icycs/2008/3398/00/3398c198.pdf
Seems to have things registered out of New York, but has had some activity in Asia-Pacific as well.