I've got a big Jablonski piece with a big egg-shaped hollw base like this - and, having just returned from Krakow on Tuesday, I can say for certain that there are a few variations on this theme within Jablinski glass producation. I've seen them, new for sale in the shops.
An interesting thing I noted a while ago, was that a piece the same as mine but in a different colourway was signed by another artist - a female. I am presuming she signed it because she made it, but it is still as far as I am aware, Jablonski's design.
I'm not saying I think this IS Jablonski - just that his is a name to consider.
It is rather wonderful.