Sure it is. I've done it in Bryce. There's one in my gallery though it isn't strictly 'toonin' it's z-ing. I've found the easiest thing to do in Bryce, anyway, is to select everything in the scene except the ground plane and camera, group, then set the zSize to some very small amount. As in Poser, setting materials (bump, diffusion, ambience, etc.) will change the look.