Bone marrow and rice is one of my favorite combinations. You really only hear about Risotto Milanese, that famed dish of Arborio rice cooked in marrow with stock and saffron, but the idea of using bone marrow with rice is a fungible one. Any kind of starchy rice will do, and any kind of bone marrow, too.
Marrow is such a useful part of animal to have around. It can be entirely rendered if you're in need of cooking fat or it can be left whole and roasted if what you want is a squishy thing to spread on toast.
You can get your butcher to slice your marrow bones the long way or the short, the advantage of the latter being that the sections of marrow pop right out of the bone like pegs in holes. Any short-grain, starchy rice takes well to being sauteed in rendered marrow, then cooked in wine and stock, and the starch of the rice makes for a thickened and creamy sauce.
If, like me, your pantry is stocked with Chinese and Japanese ingredients, then you might think of using rice wine instead of white wine, ginger in addition to onions and garlic, and dried shitake mushrooms in lieu of porcini or morel. (But then, you know, the fungi are just as fungible as the marrow. Sorry, had to go there.)
Though you won't often see this in restaurants, I'm partial to adding some cooked brown or wild rice to risotto dishes, something I first saw being done in the Zuni Cafe cookbook. Unhusked rice, aside from giving the dish more textural contrast, plays another important role in the dish: the firmer grains remind you, with every bite, just how creamy the starchy risotto really is. Otherwise, by the fifth or sixth bite you start taking for granted the richness of the dish. At least, I do.
Finally, buy more marrow bones than you think you'll need. To each serving of rice, add one segment of roasted bone marrow, which the diner may eat with toast or spoon onto the rice for an extra boost of marrow-y goodness.