I would save a bit more up, and go straight to LED.... I still have a silly smile on my face when I flick up to Main Beam, and the Light bar comes on...
Best quality 55w Halogen just tip the 1000 lumen, my light bar does 19200lm.
If you do not like the "Bar" style, go for the smaller spot light style ones, not quite as high in the Lumen output, but 4 of them would still be pretty good, and any one light would have over twice the light out put of a halogen one, and still use less current.
Mounting is easy.... just use the old gutter style roof rack mounted over the windscreen as Richo shows in one of his early posts... Means you still have the roof bars free to use when needed.