Basically the thing with elance is if you have a high-paying skill set you will have to prove it. No one cares what your resume is because you can just make up all the info and people don't really have the time to double check your info. You will have to take a few lower-paying jobs until you get on-site feedback and reputation at which point you would be able to successfully bid on high-paying jobs. Also, it can take awhile to find a provider, but once you find one, you can usually get repeat work if it is good.
I have found the same thing angry about the hit and miss results. That works in your favor OP, as if you don't screw up (which half do) you will get plenty of work. The tough part is just landing that first high-paying gig. Once other providers see someone is willing to pay you big $ and is willing to re-hire, they won't hesitate.
I only use sites like this now for long-term projects. I will hire everyone with a pulse who applies and give them all the same minimum-bid task. Whoever does the best work at the best price will then get the long-term position. This has saved me so many headaches and wasted money in the long run.
For short term projects I have actually had the best results going to forums on whatever service I am looking for. Anyone who is trolling a forum on graphic design is bored enough to work for a low price and interested enough in the material to do a good job. Just had a top-notch header/logo designed for a new site for 25$ with a revision!