Just thought I'd share some good news with everyone. Pentax lenses are now available for rent at
cameralensrentals.com. They have perfect reviews from resellerratings and their prices look competitive. They even have a 15% off for first time renters. I'm planning on renting a lens from them soon for a trip. They ship all over the US.
Hopefully getting my hands on expensive glass doesn't get me too spoiled!