The limitation will probably be the unit which the oven is fitted in. However it can be done with a bit of thought.

Most hobs fit within the depth of the worktop so the cabinet below shouldn't really limit you.
The question you need to ask is immediately either side of the hob at worktop level: If it is a wall, you will need some worktop, say 15 or 20cm, and this will be specified in the hob's installation instructions. The reason for this is to do with heat transfer to the side wall and safe combustion of the gas burners.
If there is no wall immediately to the side then there needs to be a cabinet (or at least more worktop, say 20cm plus) as you can't safely have a hob with nothing to stop anyone knocking into the pan-handles.
Provided these 2 conditions are met and assuming an adequate gas or electricity supply for the bigger sized hob, you should be able to install a hob that is wider than the oven.
Hope this helps.