I remember seeing those "try before you buy" racket rental before, however i can't seem to find it now, was it from WinningCycle? perhaps they taken it off their website, are there any other vendors out there provide this kinda thing? thanks.
Yos sports I heard Yo's Sports has this service. They allow you to demo a racquet for $5 a day. If you end up buying a racquet from them, the demo fee will be deduced. I read it from here long time ago. You should call them to check it out.
Brown's Sports does it, $10/day and if you buy a racquet from them, you get the $10 off. It's abit steep compared to Yo's though in terms of price.