Hi nightbeam,
Indeed the HID's are more powerfull, but one thing needs to be mentioned:
In this case you need instand on capebillity!! The HID's need time to start up, some do this quite fast, but still need some 10 seconds!
Maxabeam does not even have the lumens-output of the 100watt halogens, but with its high surface-brightness and instant-on, its definitely a "shock and awe"- device. But this doesn't help you because of its prizetag!
The best I can think of: The standard 100-watt bulbs in spotlights mostly have lower surface-brightness compared with the top-projection bulbs of for example Osram..
The Osram HLX 64625 (12volts 100watts 3600lumens 50hrs bulblife) has about the highest lumens-output and surface-brightness possible (in the 100watt halogen world). And with a little overdrive, it will be a monster! (with only about 5 hours of bulblife left tho..)
So if you have the skills, mod your light with the 64625.
EDIT: 3000 uk pounds for a Maxabeam!!!!!??? Basic pakkage is about $1850 to my knowledge !!
Regards,
Ra.