I'm afraid CRTs are out of production. The only way to get one is used and everything available used was built about two years ago which means they aren't likely to survive more than approximately two years.
Basically, due to the market outright rejecting CRTs (they aren't "fashionable"
), it is bad idea to get one for support sake.
I was faced with a similar situation as you not even a year ago (my 17" CRT died). I got something similar to this:
SAMSUNG 2443BWT-1 Black 24" 5ms Widescreen Height ...
Basically, you trade a decrease in response time for an increase in real estate (pixels).