Just remember that when you mix voltages in an enclosure or raceway you lose any latitide you might have had for "low voltage" in art 725. Everything is now treated like line voltage.
Oh boy, I hadn't even started to read 725 before now. The definitions for class 2 and 3 circuits seem overly complex. This section is going to take some studying.
I wonder wether there are some practical issues at play as well.Such as some current being imposed (through induction)on the DC circuit causing havoc with the circuits on the DC power run. To be safe i would go with the rule of thumb of not combining one with the other. Along the lines of even if it is permissable -should it really be done??