Good sleds are hard to find these days. Might be liability issues, since a fast sled can be dangerous for little kids. You can make a dangerous fast sled using an old pair of skis and a plastic tub “sled.”  Jeff Potter, chief blogger at on Out Your Backdoor wrote to me with instructions:

My brother Tim created a neat homebrew sled design. I made a couple of them for our kids for Xmas. What you do is take a plastic tub sled ($10 hardware store) and screw a pair of XC skis to the bottom of it. You can also use downhill skis—better for rough use. You can add a spacer of 1×3 firring between sled and ski to get some height for floating better over fresh snow. Use short, stout screws, Gorilla Glue (expands) and big washers to avoid pull-thru. Then glue foam-padding into the inside. This sled runs straight, smooth and far. Definitely the fastest on the hill. You’ll be a big hit!

It’s dangerous because you can’t steer. But it’s fast. Pictures and inspiration were found on Out Your Backdoor.