@bagginsbill:
For many fires, a single point light might give reasonable appearing illumination of nearby figures.
However, there are circumstances (i.e. big fires) where the flames are quite tall and you will see a distinct variation in luminance and flame colour from the heart of the fire (where the fuel is being broken down by pyrolysis) to the tips of the flames (where the vaporized fuel has just about all been burnt and the flame temperatures have dropped so that the gasses are not glowing so strongly). Even where the flames are mostly uniform in colour, the flame density tends to taper off with height - hence the luminance will change with height.
If the flames are significant in height compared to the figures (and they are quite close to the fire), then there should be a corresponding variation in the colour and degree of illumination too.
A wood or coal fire also tends to have a lot of less bright red-glowing embers in the base of the fire compared to the often oranges or brighter yellows of the flames. Furthermore the illumination from a fire is often highly non-uniform with complex partial shadows/bright spots caused by the solid fuel and/or flames and/or smoke.
e.g.: Photo showing some of the variations in colour and luminance:
http://pixdaus.com/pics/1210046743BYpAfLq.jpg
also, check out Romanceworks' "Ultimate Fire" which shows how non-uniform the fire can be (warning nudity in this link):
http://www.renderosity.com/mod/bcs/index.php?ViewImage=15547

So, I don't think that there is a "one size fits all" solution - especially for bigger fires.

If colour transmittance could be handled in Poser, then I guess you could use a single white point light with a graded (low = red to high = yellow) and irregularly shaded (i.e. using dark er and lighter patterns) spherical filter around a white point light.
Regards,
Jovial.