I guess it depends what your kids bikes are. I built this for my (and friends) mountain bikes. All of our bikes have quick release wheels so its easy to pop the wheels out and secure them. It held 8 bikes, but it's been revised, narrowed, and might only take 6 now. I looked at a lot of options before I decided to build my own. I really wanted to keep the wheels on but the bikes take up so much floor space that way. I don't trust the walls to hold a 33 lb bike without falling apart.
With bikes. Pics aren't that great. There's about $28k worth of bikes in these 2 pics, no way in hell any of them are going on my front bumper!