There is a finish that I use for the mahogany on my boat that I consider to be pretty bullet-proof.
I start with three coats of West System Epoxy, using the 105 Resin and the 207 "special clear hardener," thinning the first coat by 10 to 15 percent, and sanding between coats to get a very flat finish. On the boat, I follow this with 3 coats of a marine varnish with a high UV protection, since the Epoxy has no UV protection. For an indoor project like this, I would instead use an oil based polyurethane, using clear poly for the first two coats, and then, on the last coat, using either clear, satin or eggshell poly, depending on how much shine I wanted on the finished product. (I would probably use satin or eggshell, to keep the base from being too shiny, and focus attention on the model itself, rather than the base). I think that is about as oil-proof a finish as you could get.
One other thing I'd suggest is to use a very fine and straight grained wood, cut to show the quarter grain, rather than the "cathedral" type grain you see on the flat-sawn side of the wood. I think that using a broad grained wood, like oak or walnut, or using any wood that shows a lot of grain, detracts attention and ruins the scale look of the model. I'd use something like maple or birch, if I wanted a light colored wood (which I prefer), or possibly some fine grained mahogany or cherry, quartersawn, or even ebony if you want a darker color.
