Foster, who recently spoke on a panel about the subject, has experimented with contingent fees in a handful of patent cases and is happy with the results, noting a recent win.

Our client was small and the defendant was huge. The client was worried the defendant would outspend them and cause us to settle for less than the case was worth, so we worked out a deal. They only paid 70 percent of our normal hourly rate and if there was a favorable event, we would get more money, he said.

The case settled after three months, the client was able to go up against a defendant with bigger resources, and the law firm earned a substantial bonus that exceeded what it would have made had it billed at an hourly rate.

Contingent fee arrangements can also work on the defense side.

You see that more and more, said Joby Hughes, a Houston attorney who has carved out a niche handicapping and financing patent litigation. You keep the verdict below X amount of dollars, and you get a bonus.

For example, a defendant may agree to pay a law firm a percentage of its fees based on the results.

If you keep it under $10 million, we'll pay you 20 percent over your fees, or we might pay you a $1 million bonus. If there's a zero verdict, we'll double your fees, or pay you a $2 million bonus, Hughes said.

The upside

Paul Hayes of Mintz Levin in Boston said companies can benefit significantly by striking a contingent fee deal.If you're in-house counsel for a $3-4 million company and you ask how much it costs to go against a Microsoft of the world, I'll say you have to budget $2 million and you need four years with a 50 percent chance of winning, he said.