That annoyed me. I made "Slantylane" (it was supposed to be Slantyland, but I hit the key one time too many and liked that better). You'll have to have me or Captain Jim send it to you to experience it.
I'm disappointed at the stage creator's simplicity--it's really hard to come up with a game location to create in it. I did make a simple stage based on Winters (EarthBound), a wide floor of ice with a Stonehenge-like structure and two platforms just floating near it. I wanted to throw in some pine trees, but, surprise! There are none. Did Sakurai make the creator specifically for n00bs who think of nothing but creating stages that kill you instantly, or what?
When I'm back home and my Wii is with me, fixed again, I want to make a close replica to The Summit. When the stage was first revealed, the only thing I didn't like about it was the fact that it had to break and fall. Nice concept and all, but every Brawl stage changes in some way and it'd be kind of nice if one of them stayed put. Also, without the part when there is no ground time, the stage provides a wonderful home team advantage to the Ice Climbers: slippery surfaces only they can resist. If Captain Jim isn't going to, I'll make a stage based on Team Rocket's base under Celadon, with the conveyor belts. I had an idea for a game location that would use the weird ruined fortress background, but I can't remember it.