pretty sure there is there is (I thought I did it once) but I cant for the life of me remember how atm. it was more or less accidental, one day I just noticed the lights were off with the hatch open. If I can remember Ill let you know. [edit: I did remember - see below]
I also have the removable flashlight but it was in at the time. BTW the dome light stays in (and on) its just the flashlight that come out.
on my XJ when the hatch is open you just "click" (pushed up on) the rear dome and it switched the interior lights off. do that on our the MK and the flashlight just falls out
for some reason I think it had to do with the steering wheel light stalk, like setting the dash lights dimmer on its "daylight" setting or something.
EDIT: OK checked it. just rotate the dimmer control on the light stalk to the "o" (all the way back) and all interior lights go off with the hatch open.