Heater with oven: a good combination?

Hi all, I would like to hear your opinion and experience on this one:

Once in a while customers ask me to include an oven or cooktop in their masonry heater, with the idea to cook, bake bread and have pizza parties.

I like the look of a heater with oven and cooktop, and the romantic idea to cook dishes in and on your heater. But to my opinion combining the two will always end up in a compromise ánd a very complex heater.

What is your experience with combining these? And how do your customers use the oven, if at all? What is your favourite: black, grey or white? Any info on temperatures is welcome too:).