Wear any headphone long enough, and it will become uncomfortable and you'll have to adjust. Each time I put the M-100 on, or after I give myself 5 minutes break, they feel very comfortable. I haven't tried on the CAL!s or Denon D7000, but the M-100 are the most comfortable closed headphone I've ever worn. I do find that the AKG Q701 and AD700 are more comfortable during listening marathons, but I also find those options unsuitable for portable use. I might be interested in XL (DD?) pads, but I'm still enjoying the overall comfort of the M-100 in the meantime, and if the XL pads sound worse I might pass on using them.
The issue isn't worth losing your cool over. It would be nice if the headphones were fully circumaural and didn't touch the ears under any circumstance, but that would directly affect their portability (and use in public), and I already have headphones like that.