I bought myself a mini Gretag Macbeth chart specifically for use making DNG Profiles at weddings. It works like this, When I'm doing the family shots under repeatable lighting (strobes, whatever) I take a shot of the Gretag instead of my usual Whibal and when I get home I build a specific profile for that location and bingo I have incredible and accurate facial colours and tone for that part of the wedding.
In other words, any time I have a sequence of shots, in lighting which will not change shot to shot, I can build a profile for those shots and get far better colour than otherwise. Don't argue, it works!
Problem is that you end up with a huge amount of profiles under the profile tab - and if you remove them then suddenly the colour and WB of the shots using that profile is screwed up.
At present I'm storing the profiles with the RAW files that they apply to and copy them into the profiles folder when needed but it's a pain in the neck!
Wouldn't it be cool if you could choose to store the profile specific to the photo WITHIN the .xmp file? The profile is only 27.4kb, wouldn't make a big deal. Of course you wouldn't always want it but it would be nice to have the choice wouldn't it?
I think DNG Profile Editor has become a sleeper feature, you don't hear anything about people using it, however it really is HUGE to those needing accurate/pleasing colour and having this functionality would be worth it. Think of a catalogue studio, they could generate 100's of profiles in a day, especially outdoors, but it would be nightmare to have all those profiles showing up in the profile tab.