My concern is of course ...... DMS formation.
That's all that I would need to stop me.
I agree, but the several people who have claimed to use this method also claim that DMS is not a problem.
According to the reports, DMS is mostly only noticeable in lighter styles, and especially using pilsner malt. With a proper boil, the amount of DMS potential in heavier ales is not noticeable. Sort of like HSA is a concern, but only if you are very uncareful.
Just for clarity, I would not do this unless forced to, I like my CFC. But, for those that don't have the cold water source, or who want to shorten the brew day (yes, you have to do more work the next day, but that's ok for some), it almost seems as though it's worth looking into.
I'd be curious to see some test brews, using a split batch for comparison. Half to be cooled, the other half no chill. Pitch and ferment the same and see what happens over time.