Harlequin just made a new digital imprint company and publically announced the start of a new company. For authors interested in joining up, you can find submission information on their blog.
They will pay twice a year and the minimum word count is 15k. They were still discussing the contract details so they wouldn't divulge that info.
However, in the print market, they pay 6% of sales which can't be sustained in the digital market without the larger sales numbers. The competetive rate is 35-50% from the other digital publishers. I am curious, what they will decide on because authors have to eat too.