Nothing specific, apart for the sites you know. I have no experience on those sites but I've heard of people that have found good professionists there (of course they wont charge you 5$/hour but maybe 50$/hour).

NB I could probably add also anyfu.com for highlevel experts (in the 200$/hour range) but it has not launched yet (it's done by Justin Vincent and Jason Roberts of TechZing podcast fame)