Swing Help

[bchafin]

With all the talk about playsets it got me thinking about what I would like for my DS. There is a large playground that we go to occasionally. He loves all of the climbing equipment. He has never been into the normal swings, but they have these swings that are great. They are HUGE saucer/discs that are attached with four ropes. they are concave, so you won't slide off. They are big enough to pile multiple children on or an adult with two small children (speaking from experience). I would love to be able to find this for our future playset, but I have done every search I can think of and can't find it. Does anyone know what I am talking about? Does anyone know where I can find it?

TIA
Barb