"The best" way to offer both UVB and heat will vary on several factors. Primarily A) The size of the enclosure, B) The heating needs of the animal & C) The UVB level required by the animal. While other things will also impact your decision, in my opinion/experience, these are the three main factors (and in that order).
 
For my 50" Tegu in an 8' enclosure...
 
I use a 4' fluorescent UVB bulb and two 100W bulbs. They are set up so that they overlap in the middle but both also shine on an area alone. This allows my Tegu to bask in UVB only, heat and UVB or heat only...
 
 
 
The incandescent UVB bulbs (Mercury Vapor Bulbs) do exist and several manufacturers make quality bulbs that live up to their advertising. Though in my opinion, the cost vs effect of them do not make them worth while. Yet when/where simplicity and practicality are high priorities, their value increases.
 
 
 
aquaculture;4907315; said:
Odd, but I guess designing and then selling a uv bulb that lasts wouldn't make them enough money.
 
That's not it at all... There is a chemical that is added to some bulbs and the heat/light causes a chain reaction that results in UVB being emitted. Thus the chemical gets 'used up' (degrades) over time and becomes spent.
 
If they added more chemical it would make stronger UVB, but it wouldn't make it last any longer...