Hello,
after annoying su_v with this for a while in IRC I'm taking this to the list now and hope that someone here can have a look -- otherwise I will try to file it in launchpad.
The bug (?) I see is that Inkscape fails to apply a changed display color profile. More precisely, when I tick "Retrieve profile from display" in the settings Inkscape correctly gets whatever I set in the X atom. When I change the assigned profile while Inkscape is running it doesn't change the used profile though.
After digging into the code a bit I found that src/ege-color-prof-tracker.cpp correctly notices that the profile was changed in handle_property_change(), it manages to extract the correct data and calls set_profile(). Afterwards fire() is called and the innermost if() is also reached, resulting in the g_signal_emit() being executed. This looks all fine and dandy. However, there is no further reaction I could see. I didn't try to understand what signal exactly was emitted there and what pieces of code connected to that, so I can't tell if the signal isn't caught by anyone, or if the subsequent code is buggy. All I could notice is that the newly found profile is not used.
The easiest way to test this is using a regular sRGB profile and one of those profiles that swap color channels (BRG.icc or the like). I would expect that changing the display profile makes a noticeable difference then.
I hope that it's just a small fix and that it can be taken care of for the upcoming release.
Thanks for your attention, and thanks for Inkscape.
Tobias