Be happy you can rent stuff. There is no place here where you can just rent photo equipment. If it's not already in your bag you can forget it. No one sells Pentax gear at all except for the occasional used listing on Craig's List. I can rent a decent studio space, but even then I'd have to bring my own lights and backdrops.
Once in a while someone will bring something cool by way of a lens to the photo club and I'll miss out on using it on my camera, but I don't mind all that much. Most of the time one of the guys will offer to let me use one of his backup Canons or Nikons as the case may be but I'm not all that tempted by them even with a pretty lens on them. In the end I'd rather settle for my 75-300MM and a converter if need be than swap out cameras.
I don't view having a Pentax as an inconvenience. I view it as an opportunity to think outside the box and to out perform the expectations of others who don't share my love for the brand. Half the time while the guy with the Canikon I'm partnered to is trying to work a behemoth of a lens from back up on a sidewalk so he can take a picture of a bird in a lake I'm walking right up to the shore of said lake and I'm getting it as best I can before the darned bird up and flies away! Yeah, he might get the portrait shot before I do, if he's lucky and actually gets the big lens to work in time, but I don't care.
It's usually not a competition my photography. I take pictures WITH other people sometimes but I seldom actually compete against others. I'll sometimes enter a contest, sure, but honestly it's mostly for the experience and I don't care too much if I actually win or not.
I'm just as happy to see Mr Canikon take a good shot as I am to get one.