What color, white? white/blue? blue? Highest possible par with blue flourescents to balance out the yellow?
The Aqualine 10000K (Aqualine Buschke) are crisp white with a subtle hint of blue and might be the highest par bulbs that have no yellow hue at all. They are actually a 13000K bulb without the shield and closer to 110000K with it. No yellow tint at all. Good choice for pure white/no yellow high par.
There are lower Kelvin rated bulbs with more par but varying degress of yellow. Some of the 10000K's are actually much lower than rated and have a yellow tint and higher par. Some are closer to rating and whiter. Then there are the 140000 and 15000K's with more blue, lower par. Then the 20000K with even more blue and even lower par. There is a 12.5K K Geissman which some people like.
Depends on what color you are looking for and how much par you need. I'm far from an expert BTW but anyone who helps will need to know what you are looking for more specifically.
Also, do check the Metal Halide FAQ thread at the top of this page and chekc out Sanjays website listed in that thread for comparisons of all different wattages of bulbs.
also coralreefecosystems.com has pictures of several different bulbs so you can see differences in spectrum and intensity to a lesser degree.