30x Incandescent light bulb in parallel ? + dimming
You could easily connect them all in parallel. or in any grid ie (3*10 or 6*5) and just control the input to the grid independently. As others have said incandescent bulbs is mostly a resistive load. If you go with ,say 5 in series and each of those 5 is in parallel then you would require 7.5V @ 1.8A. Choosing a configuration is simply a matter of what you have available.

Except for requiring more power than LEDs the incandescent bulbs can be pwm much easier. You might even be able to get away with a much lower switching frequency because the bulbs will tend to filter higher frequencies. 

Series is easier to switch m but if one bulb do fails , the whole light fails. Going parallel you need to switch a higher current but its trivial to find a blown bulb. Using a grid like arrangement mixes these two features partially so you get lower switching current than when all is in parallel and its easier to find faults than when everything is in series.