We're 16:9 as well. We had widescreen tubes for a couple years but they fell out of favor very quickly once LCDs became less expensive.
You haven't said if you have an existing monitor or not, or if you plan on playing with a computer or actual arcade hardware. Giving us that info will help us, I think.
You have a couple of options. Your TV has SCART, most likely. You can wire it directly (
more or less) up to the RGB output of an arcade board and then it becomes an arcade monitor with the proper sync rates and all of that. I do not know, however, what the widescreen nature of the tube will do to that picture. Will it display a 4:3 picture or will it be an edge-to-edge picture? I don't know. Maybe your TV menus can correct anything that isn't good. Again, I don't know.
If you think you can find a lot of TVs of the proper size to match your (perhaps) existing arcade monitor, you can look up your existing arcade tube
here and find compatible tubes that are often found in TVs that way.
Clean arcade CRTs are becoming hard to find, no matter where you are. Fortunately in the US we have a lot of folks still using CRT TVs and they can regularly be found in yard sales for a pittance. I bought 4 this weekend for $6 total, and all the tubes are perfect.

That tool I linked to above can help you work out compatibility between tubes, but I don't know if it has widescreen tubes, or not.