I was in the same predicament with a tail for my old FZR, a friend had an R1 race solo in fibreglass, so I made the subframe with steel that cost $19AUS and some mirror stainless I had lying around, then painted it! the indicators cost more than the whole rear end!!! I made the number plate hanger as well.
Def worth a try at making one, you may surprise yaself!
Some shots during and after the construction, took about 8hrs work all up.
Just some ideas, don't feel trapped by lack of factory or overpriced parts av a go!