Baking soda breads are quite cake-like - it's pretty much a cake recipe with no sugar. But if you don't like the lightness, you could make it with wholemeal flour, which tends to make anything denser, chewier (and higher in fibre). Or substitute in some rye flour for the same effect. Ooooh, and I like whole walnuts in baking. What about some sunflower seeds too?

Flour is messy - and, yeah... alcohol and measuring. But I can't talk, since I don't ever actually measure anything while baking.