dBoxBox is a perfect place to figure out how to generate all the contact points. The code is hard to read so I wrote an article about it (see below). The trick for making contact points is to transform both OBBs into the model space of one of them. If you understand this all then you can greatly simplify the face clipping. This should all be in the ODE. Another place with an easier to read OBB to OBB manifold creation is in Ian Millington's Cyclone physics engine. There are like 4 or 5 different smaller easy to read functions that gather up the contact points. IIRC I don't think he did any clipping optimizations and does calculation in world space.
If you want stability then you'll just want to read Erin's stuff on solving constraints. Stability is largely about solving a system of equations, assuming you have proper collision detection. If you run sequential impulses on all the contact points you should have pretty good stability for starting out. You probably won't need to do manifold reduction immediately (reducing from a large number of contact points to only a few of the more preferable contact points), and can implement this later if needed.
For generating the contact points and doing collision detection for OBBs I wrote an article about this: http://www.randygaul.net/2014/05/22/deriving-obb-to-obb-intersection-sat/
But really if you don't understand the impulse solving and how to make it stable you should start with Box2D Lite and make sure you understand the contact caching, warm starting, and the contact constraint. Then, if you can write this code yourself and do the math, it will make sense when you try to do things in 3D. If you want to make sure you really understand the math you can take this naive solver here: https://github.com/RandyGaul/ImpulseEngine and convert it to use sequential impulses. It can be noted that the equations being solved are actually identical between the naive implementation and Erin's Box2D, but how they are solved (iteratively with solution caching, or naively) makes a big difference.