As a bonus, the research could also show if there is a bigger increase in sales for online retailers compared to physical retailers accepting bitcoins. This could encourage more stores to accept bitcoins.
i dont think that there is that much research out there concerning this, and what is out there is vague and dated. but I can think of one example however without having hard numbers: the Gyft mobile giftcard app. They were one of the few ways that you could spend bitcoin to buy consumer items (they had alot of restaurants and popular services) back in the early days of bitcoin. everyone that had bitcoin used them at some point; im pretty sure if they held, they made a small fortune. no way to check this though, I dont remember anyone reporting on this.