I have several sets of a Bosch lamp that I got from Mofoco.com. They are $20 each and have pretty efficient lens/reflector optics (I'm an automotive lighting guy at work). The size is a little over 7", the output is pencil beam. I put 130W bulbs in place of the 55W supplied and have been satisfied. I have a set on my front brushguard and on the roll cage facing rearward.
The first time I bought these was about 10 years ago. They came with covers back then, but those are sold separately now. Still a great price. Construction is good quality (old design, but very robust).
To see them, go to mofoco.com, then download the catalogue. Click on the page number at the top right to turn to page 13. They are at the bottom. Part number 23902C.
Hope that helps...