I used to work within that industry and they are very hesitant about selling the component parts. Many of the bezel shapes originate with a designer style and the companies want to control how that style is used. Once you've worked in the industry you can look at a gauge mounted in a vehicle and immediately recognize who made it - companies don't want to confuse their market identity. Finally, many of the companies were originally formed by a person or two who would take technical info and strike out on their own.
First, check with some of the companies who do custom dials and gauges for the marine and industrial vehicles- Datcon, Teleflex, Faria. Then check with the smaller outfits who work on some of the smaller nich applications - FW Murphy, Dixson, and Isspro. The landscape in this market probably has changed somewhat so other companies who years ago only did high volume may be more open - VDO or Steward Warner
Plastic bezels on plastic housing take design work and are a bit of an art to both compress the seal reilably and ultrasonically weld. You will do better with a metal bezel rolled on a plastic housing, or easier still - metal bezel rolled on a metal housing. In either application reliably sealing takes some knowledge along with the proper custom crimp/roll tooling and a press.
Lastly, you might research some of the mechanical pressure gauge manufacturers to see if you can locate a suitable enclosure, but many of these have changed to full digital or shut down due to offshore competition. Also, you might check out other 2" gauges made for other boat or car accessories to see if there is a independent gadget maker (i.e. depth sounder, hour meter, etc) who has an enclosure that would work.
