I've done some more research and found 2 more frames that look promising.
The first one is the TanTan FM10 which can accept many different shocks including 200x57 which will give around 150mm of rear travel. My fork is only 140, but it shouldn't be too much of a difference from a 150 shock as far as geometry changes. This frame is 200g heavier than the p1 and has a bit slacker geometry since it is more of an enduro frame. This frame is quite a bit cheaper than the p1 though at $600 plus $100 shipping to the US.
Next up is the Carbonda FM1002. I really like the look of this frame and it is specced with a 205x60 shock which I think I could get away with putting a 200x57 instead which would shorten the travel some and lower the bb. It is also meant to have a 150mm fork so a 140mm would lower the bb as well which might be a concern but I haven't tried to calculate that yet. This frame is about 120g heavier than the p1 and has an even slacker head angle than the FM10 and a much longer wheelbase and reach than the FM10 and the p1. The geo of this one is quite different to my current bike but I really like the look of it. Im not sure the price on this one as it is not listed on their sit and I am also concerened with quality issues that Carbonda has had in the past with cracking and fitment issues on other frames.
I think the FM10 from TanTan or the p1 is a better fit for my components and more similar to my current diamondback, but I'm having a hard time deciding between the three frames p1, FM10, and FM1002. Any feedback would be appreciated.