http://www.deskdivers.com/Site/EZM.html
Here's some info on Sinn's oil-filled "hydro" models. The current model, the UX (EZM 2B), is based on the EZM2.
The only other oil-filled watch I know of is the Bell and Ross Hydromax, but I'm not sure when these were last available.
The UX is a fantastic watch - great build quality and legibility.