Hi nanoq.
There is a Ritz Camera store near the Florida Mall in Orlando that carries a decent amount of Pentax gear. I go in there often and bought the Pentax 18-250 there recently. They usually have the 50-135 in stock as well as a few others. There's a gentleman working there that is very helpful but I can't remember his name off hand. He's middle aged, thin, with glasses. There is also a Ritz in the mall but they don't seem to carry Pentax lenses so I wouldn't go to that one.
Ritz Camera
Special Tee Golf Plaza
1233 W. Sand Lake Road, Suite 8
Orlando, FL 32809
Phone: 407-240-6998
Ritz Camera - Florida Mall
I would also call Colonial Photo and Hobby. They usually don't carry much Pentax gear but it might be worth a phone call to see. Other than that Orlando is pretty dry as far as Pentax is concerned.
BTW, if you have any questions about Orlando feel free to ask. I've lived there since 1969 so I know my way around.
Enjoy!
Slick