Valve....New ?

[Nick]

Do you reckon the fluorescing is crucial to the devices operation or designed to enhance the overall visual appeal or a combination of both ? If it was good to 30 Mhz (the valve) I wouldn't mind one of them to mess about with, wonder what the specs are.

The anode fluorescence is due to this really being a VFD, made on a VFD production line, by a company that makes most of the world's VFDs

The anode coating of VFDs is what makes VFDs so useful, but its not essential (just cool). The cathode coating, OTOH, is vital - VFD manufacturers have developed coatings that make the cathodes perform flawlessly for many years - at least 3.5 years (30,000 hours) of continuous running - old purpose-built triodes like the 12AX7, used to need replacing fairly often, with lifespans of less than 10,000 hours. 

So, to save money, Noritake have used a standard VFD production line to do this - VFD form-factor, VFD internal construction, VFD anodes, grids & cathodes, VFD pin-outs etc. etc. As Mark correctly points out, pretty much any VFD can be used as a triode, some even up to RF frequencies...

Sensible move, really...