Ceramic lamp is really not advised.
It will decrease a lot humidity rate and you will have to be very careful to maintain, at least, your substrate wet.

I think that the ideal solution is a heating cable (With sufficient power to get the right temps) fixed on the sides of the tank.
Then it will decrease less the humidity than a spot and the other advantage is that you can manage temps by plugging the cable on a thermostat.
Then you can give natural light or "Non heating light".

I do this with my pacman frog (50W heating cable in a 30x30x30) and the light is provided through a Reptiglo 2.0 UVB 13W from Exo Terra.