An adult beardie needs a VERY large tank. (Relative to a 10gal) Mine is in a 55gal and it barely seems adequate to me.

You might be able to go with a single crestie...and turn the tank up on its end so it is taller than it is wide. But really...it'd be really hard for any of us to predict what you'd think was cool.....and going strictly on the stereo-typical "cool factor" I can't think of anything that would be suitable for a 10gal tank.