From the below figures I think we can assume that the maximal color temp difference between the alpha bins is around 100 Kelvin. The old Habicht 8x30 from 1961 is a bit more off and differs about 200-300 K from the rest. Unfortunately no figures for the Swaro SV and Zeiss FL here but probably the FL is closer to the SF than the HT.
If you have some kind of photo editor on your computer you could experiment with a 100 Kelvin difference (most editors can set color temp) on a photo or just a white patch (easier). In a direct comparison it's quite easy to see the difference. But in a blind test it's quite a bit harder to identify what photo is what. Haven't seen any figures on what color temperature the human eye can discern but I think that at 50 Kelvin it's getting difficult even in direct comparison.
Habicht 8x30 (1961) - 4547 K
Leica UV HD+ 8x42 - 4781 K
Nikon EDG 8x42 - 4803 K
Habicht 8x30 (2009) - 4841 K
Zeiss SF 8x42 - 4842 K
Zeiss HT - 4872 K
*From Tobias Menles comparison chart I get these color temperatures by using auto white balance in Apple Aperture. Higher K-value means a cooler image.
http://www.birdforum.net/showthread.php?t=315713&page=2