Yes, Toyota Yaris R4 with Oreca’s R4 kit is being built by Evolve Motorsport in Warsaw. They say the price of the Yaris R4 is 20% lower than any R5 car and the running costs are up to 40% lower. The car is going to make its debut in the first half of 2018. More about it here:
http://www.evolve-motorsport.com/yarisr4evolve/