What would be the best bike frame to build a gravel bike? This handsome devil road bike is what im kinda looking for but i want some suggestions of what is the next best thing to start with, any ideas?      

I was looking for a good bike or bike frame that i can use to build up my own "gravel bike". I have gotten recommendations to use a older touring bike frame with the tire space or an older hybrid bike. I have found one good bike but i have lots of options of used frames that i would rather choose from.
When I was considering building a gravel bike from an older frame I considered two basic frame types: cyclocross and drop bar commuter.  A light touring bike frame would be a good basis as well, although many older touring frames were built for stronger 26" wheels.

The primary features you are looking for are cantilever brakes and clearance for at least 32mm preferably 35mm or more tires. Another is possibly the ability to mount fenders, which you will find on a commuter or tourer.

Steel seems to be the material of choice for durability and comfort, but if you value light weight Al can be made to work. It really depends on what compromise you want to make.

In terms of geometry take your pick between more aggressive cyclocross or more relaxed commuter. One thing to bear in mind is older cyclocross bikes predominantly have a 'Euro-style' high bottom bracket.