Memory chips can withstand high heat (up to 60 degrees maybe :dunno: ), I think even if your hand gets burnt from the heat. The CF will still be able to withstand the heat and function.
Not all the heat is from the camera. The CF cards them selves get hot - my CF cards get pretty toasty when in my laptop as well.
The D7* powersupply is in the 'grip' which doesn't help the heat in the CF area, however I would rather a hot grip than a hot CCD chip.
(Image noise is directly related to the temp of the silicon).