David,
I will love to see your results on those tests. There are differences in light color temps at output levels for some strobe systems for sure. The Profotos, Elinchroms and Broncolor have always prided their rather precise color temp outputs, regardless of output power. I have found my DynaLites to be pretty close there also, but probably not as close across the entire range. There seems to be a lot of variation with many others, so it would be nice to know how good/bad some of these are.
I would choose Elinchroms for most consistency and just really lovely light, Profotos for sturdiness and also very nice light. The Brons are also wonderful, but they are a bit too proud of their product (expensive). The DynaLites are a bit of a compromise for very light and very portable compared to the others, and yet they can produce a nice light also. I keep threatening to change up to Profotos, just because I haul things around so much and they are less "fragile", but the added bulk and weight is less attractive.
Also on the scene now are Westcott daylight balanced fluorescents. The color temps from them are very consistent at 5400K or so. They just do not put out all that much light, but it does wrap nicely (very soft), and the units stay very cool, plus you can mix with strobes to get different accents, and that seems to work nicely. I like them for being able to shoot slower shutter speeds at wider apertures and still get a nice daylight look without the heat of other continuous lights, and being able to mix with flash for spots or highlights, while still seeing most of what you want for light coverage. (Modeling lights are o.k., but just are not the same when trying to shape the light more precisely, IMHO.)
Sorry to hijack Guy's thread, but this is valuable stuff also ;-)
LJ