You can get new CRTs on Ebay. These are mostly computer monitors but they're pretty cheap and count for something. There are occasionally new production monitors. 13" JVCs and such. I recall seeing a brand new in box PVM once. On another forum a guy posted about his NIB Olympus OEV. And if you know a TV repair guy there are new replacement tubes for monitors. Trinitron tubes pop up.
On this topic, this morning I snagged a new-in-box JVC TM-A13SU production monitor for $35 on ebay. Its best connection type is S-Video which is fine by me... I'm covered by my other monitors when it comes to RGB. I'm more interested in its diminutive size and weight, how the P22 phosphors differ from the higher grade SMPTE-C, what games look like on its modest 325 TVL... and of course the fact that it's brand spanking new, zero hours on the tube.
On Atari Age it's mentioned that this is the successor to the TM-13U which itself is the inspiration for the Commodore 64's 1702 CRT monitor (also made by JVC). http://atariage.com/forums/topic/247508-modding-the-jvc-tm-a13su-monitor/