Hey there Sebastien, and welcome to the forums! Thanks for getting in touch.
That’s a great question. I don’t have a copy of the Product Vendors plugin, but I just checked out the link you sent and can see how useful it would be to allow vendors to create their own tickets.
Right now, vendors can come in and create their own events on the calendar by using our Community Events add-on, but you’re right that they would not be able to create a ticket when they create an event in the way you are looking for.
This sounds like a great feature though. If you don’t mind, please put it on our uservoice page. This allows others who are interested in that feature to easily voice their support. We frequently review suggestions there to find out which ones are popular, then we implement as many of them as we can.
Cheers!
Geoff