Kwik Kraft Hulls
Kwik Kraft is/was the dominating hull in New Zealand.
Designed and built by a Kiwi, Tony Ward, these hulls are tough, durable, expertly built and good turners.

"Kwik Kraft no longer makes aluminum race hulls, as near as I can tell."
Correction to above 1/14/2007:  Tony Ward sold the business in 2001, but it is still called KwikKraft and they still make race hulls. Brian Cottle has owned the company since 2001 and they have been
making race hulls all this time. Here is a link to their site:http://www.kwikkraft.com/
The bottom left picture is Rob Pooley at the 2004 Worlds, the bottom right picture is Mark Cromies 2007 unlimited boat.

Eagle Hulls
For about the last 12 years producing the fastest race hull has been the single minded goal of Rob Chrunyk and the folks at Eagle Racing. Eagle hulls hold more records and have won more races, championships and world titles than any other hull. They make a fine 21 foot tunnel in both standard and lightweight, and a 19 foot step-tech in both standard and lightweight. The tunnel is intended for B, A and Unlimited racing while the step-tech is excellent for FX class.
Check them out at :  OutlawEagle.com
If you are interested in the ultimate pleasure boat, OutlawEagle also makes the best performance/family jetboats you can buy.
Outlaw Eagle is now owned by Terry Sharkie and Dale Whiteside, both racers.

 

Keelowcraft Challengers
Neil Ross makes a line of tunnel race boats in New Zealand. I don't know much about them, got to look over one for about 20 minutes in a parking lot one time. Here is a link to his page: http://www.jetboat.com/raceboats.html
This is a picture of Neil at the 2004 Worlds racing one in FX class. (Which he won)

Provost Race Boats
Dave Provost has been working on and perfecting his unusual line of wing in ground effect hulls since about 2000 in the US. I am biased as I have owned two of them, they are the best handling and most efficient hull I have owned. Nobody thinks they are pretty except for Dave (and me), but everyone has taken notice of them over the last few years as he works to refine them. So far they seem to be able to offer comparable performance on less horsepower, enhanced stability and a total lack of a tendency to shear. The line is called "Cobra" but are also known as wing boats. If you are interested, let me know and I can put you in touch with Dave.
E-mail me at 

 

RPM Parron Mitchell race hulls, available in the U.S.
 Parron worked with Tony Ward on that very successfull line of hulls and is now planning on selling his hulls in the US. Check out the the site:  www.speedboats.co.nz