🚀 go-pugleaf

>Does anyone know what combination of gases would provide a good
>infrared light source in the range of 700 - 1100 nanometers?  The
>intend
>ed use of the gas would be in a neon-type tube to provide a
>continuous, diffused light source.

Krypton, at moderate to high pressures.

>Alternatively, does anyone know of any continuous infrared light
>source that provides:  diffused light, can be in a bendable, yet rigid
>form up to 5 feet long, does not get hot (~ 5 watts would be nice), no
>power cycling, and has a good long life span (like a few years).

An ordinary fluorescent light with a special near IR phosphor would
do fine. I have no idea whether such phosphors are commercially available.
Alternatively, a 2500 Angstrom UV(blacklight) tube could be used to
illuminate the appropriate phosphor externally.

You could also use a huge array of standard near ir LED's. This is
probably the easiest for 5 watts power input (not output).