Painting on canvas is great, but if you want to try something different, I'd suggest painting on plywood. Plywood comes in different grades, including nice, smooth, furniture grade birch panels. Unprimed plywood is a pretty thirsty surface, so your paints will dry quicker than they do on canvas. And if you're worried that your paintings will be less 'real' than a painting on canvas, keep in mind that the Ghent alterpiece and the Mona Lisa were both painted on wood.
I'm not much of a painter but if you are going to do that you will need to sand down the wood and possibly seal it first before doing that or it will crack. Wood tends to absorb a lot of paint as well so you need to take that into consideration if its a large project.
I haven't had an issue with cracking yet. That might happen with water based paint, but I'm using oils. The great thing is oil paints are based on linseed oil, and linseed oil is great for wood. If you want a nice white surface to paint on, you can always prime the panel first.