I have to admit that I’ve started looking at some darker browns as a possible alternative to oxblood.
Stan was alluding to this in his post above- from a design perspective, when putting colors together, usually when 1 color is quite strong (your car will be an attention grabber from the moment you see it, even from a block or more away!), as is your exterior Oslo blue, what generally works best in the interior is something that, even if it's quite different, is something that's a little 'softer' or more 'neutral'. Putting 2 colors together, both which are screaming for attention, is harder to do. It can be done, but it will be a real hit/miss thing, with the results not known until it's too late. The red interior of the Spyder Chris showed above works because the silver, even with a blue hue, is somewhat softer or 'unassertive'. The same with Gordon Nichol's Speedster- that wow red/wine/burgandy interior of his is surrounded by a more neutral exterior (in this case white).
If you are thinking of a brown interior, something along the lines of what either Alan Merklin or Wingd gave examples of, note that the exterior paint of none of those cars are strong attention grabbing, look at me! colors. Even though they're all gorgeous in their own right, they're somewhat subdued compared to their respective interiors. With a strong interior color in your car there will just be too much going on. Look for something a little softer and it will be stunning.
Hope this helps. Al