Are they? That's a good question. The design looks similar enough, especially the shape of the base, that I would have thought they were made in the same shop. Looking more closely, the knobs and struts are different styles, so maybe one is just copying the other.
Current Gibellini pricing is higher than Stenopeika, but for a metal/carbon fiber camera. Current prices at
http://www.gibellinicamera.com/#!shop/c24nu
I've updated the title to include both brands.