Wanting to build up a new bike with the p18 pinion gearbox .
I say go for it. However, be aware the pinion gear box is expensive and adds a few extra pounds of weight to your build.
I would build this, but cannot find a manufacturer
Talk to Peter at xmcarbonspeed.com, I thought there was a new Chiner carbon frame that was going to be available.
Before you start I suggest to try the gearbox on some test bike first if you haven't already. The weight is not a big issue, it is in good place, but the shifting feels a bit weird - it is not that ergonomic and doesn't feel as good as shimano or sram. This might not appeal to some.