Regarding the ccled circuit above, with vin=42v,and iled=7A, and Vled=30v, As you know we see 75W dissipation in the fet and 5w dissipation in the sense resistor. (as shown in the below schematic). I appreciate that you already know this, and that we must present Greg this circuit in case Greg does not want to lay out a pcb......though that is a fair bit of power there....We possibly hope nobody accidentally switches it on when its on dry land.
Having said that, at vled=30v, and iled = 7A, there is 210W dissipation from the LEDs alone, so I suppose an extra 75W is not so bad.
You have to suspect that at these dissipations of the led bank, non sharing of current will creep in and the leds will go bang