Unusual grapevine

Hi guys,

about this time last year i seen a few grapevines for sale in the local garden centre. I did`nt take any pictures though so will have to try and describe them lol

They were basicly grapevines but they looked like they had been pruned or something so that they all had one central trunk about 2 or 3 feet high and about 1 foot wide with a little tuft of grapes coming off the top. Kinda like a tree fern but with grapes where the ferns would be.

Does anyone know how you get them to shape like that?? I thought it would be good way to grow my grapevine since i dont have anywhere to put it up with a trellis or support lol Plus it looked great.

Thanks guys.