Bike spec suggestions

Hi STers. This might be ever so slightly out of the realm of triathlons, but it’s bike-related so please don’t tear me up too badly. I’ve got a friend who makes custom steel frames and offered me a great deal so I’m taking him up. My current plan is to build a bike that I will use for long training rides and a bit of off road (mostly fire roads). I’m having him build it with 135mm spacing, disc-brake specific (for crappy weather and off-road). Because i’m not going to use canti brakes on it, I keey convincing myself that I should use a rim without braking surfaces (disc- or track-specific, perhaps). Does anyone have any good ideas? I was thinking about just some Mavic Open Pros, as they are the cyclocross standard and seem to be decent road trainers. I’m also a bit torn when it comes to the cranks. The rest of the drivetrain is going to be SRAM Red, but there are so many crank options out there, I can’t imagine that the Red crank is the best one, or even the best value. Finally I need suggestions on how to paint it – keep in mind that I can only do 2-3 colors (any more and it’s $$$) and need to include the frame builder’s graphic somewhere on the bike.