Hi,
two options for smaller HID driving lights I know of:
http://global-offroad.com/product-sites ... -4500.html (sorry, in german and quite expensive and about 5" in diameter)
http://myhellalights.com/hid_xenon_lamp ... n_HID.html (only seem to be available in the US, don't know about the price)
I haven't tried any of these, my personal dream is a pair of Hella Luminator Xenon (Rallye 4000i Xenon in the US), if they'd already be available in Germany...
I've already got a pair of Hella Micro DE Xenon, very small xenon driving lights, I only tried them once (took the bumper off and mounted them on the crush cans), they are a nice addition to the standard main beams, I just need to get around to mount them...
If you are interested in further details about the Global Offroad lights, I'd be happy to translate, etc. (no, I don't sell them and I don't know the dealer)
Do you want to run them on road or off road only?
What are the regulations in your country in this regard?
(Here, in Germany, the maximum number of main beam/driving lamps is limited to four and the light output mustn't exceed a certain value)
Sigi