Tom - if you helped develop /tweak the plane, then you might want to look at whoever your builder was (Xtreme?) - cause it looks like your Su29 is now being sold under the BVM name.
http://www.bvmprops.com/Aircraft/sukhoi/sukhoi.htm
Generally do the factories have the right to do that - or could this be similar to the Chris Hinson/Extreme Flight vs. Sammy Lee Yak design custody battle that erupted a few years ago?
There is no "Generally" answer to that question, eachdeal is different.
In my case we (Wild Hare and Extreme composites) jointly developed the 87" Sukhoi, I paid for half the development costs and did most of the testing. I trusted Xtreme to hold the price to the quoted amount and got shafted as a result.
But since I am not buying the plane any more he has the right to sell that one to BVM per terms of our agreement.
I have no idea what kind of deal the other guys you mention may have put together.
TF