Nalgene makes labware bottles with standard neck thread sizing, so you could probably find a HDPE pump cap to work with them.

Also, a few companies make reusable Nalgene aerosol spray bottles. Essentially they're spray bottles with a pump built in to pressurize the contents. It's HDPE rather than the Lexan most people are familiar with though. Nalgene Aerosol Container

I have seen some Nalgene Lexan-like pump spray bottles (atomizer?) in Walmart's Travel Section (near the pharmacy). I don't know if they are indeed Nalgene though. I didn't read the info on the bottom of the bottle.