The forex niche is a very competitive and saturated market. Binary options are now becoming more and more popular. These are usually CPA deals but are VERY successful and can make you a lot of money. http://thebinaryoptionsaffiliate.com is a great place to start for a binary options affiliate, as the guy there also helps people get setup and gives advice (mentoring) on the do's and don'ts of the industry
Forex-Metal CPA is good and you can negotiate your own customized commission options and they say hybrid commissions are possible.
I am an Affiliate Manager at Optionow.com - a top binary option broker company. Contact me at . We offer CPA and CPL.