I assume you want this for ice fishing.
I believe I've seen both the dogseld style and plastic Jet Sleds at AJ's in Meredith.
I have both types. The big and beefy plastic sleds are fine and the smaller thinner plastic sleds are less stable (obviously). If you are going to use it much the rigid hitch is essential.
Here's a picture from a few years ago of one of my boys and a friend ice fishing with the dogsled style that is being referred to.
(Yes, I realize the boys in this picture do not have helmets on... they were ice fishing and just moving slowly between holes.)