The top-end of these motors are basically the same, respectively, as the Raptor 660 and 700.
And built Raptor 700's make stupid power. A bit more than the 660.
It's only a matter of time until 700 mods start coming in. Yeah, it's already been a long time...but there's nothing inherent to the 700 motor that is preventing it from making power.
It's just the time/effort/money of the aftermarket companies to get on board...that, and there's a lot of competition out there (Kawi, AC, Polaris) that is getting the attention of the aftermarket companies, too.