As you can see here, they are selling the 2011 Cabrinha Race quad 183 by 59 for £699 and the 2012 Race, with 5 tuttle boxes and 4 tuttle fins is £1150 for the 188 by 69.5.http://www.kingofwatersports.com/cabrin ... 21465.html
The 2011 183 is based on the Aguera CR59 on which Adam Koch won the 2010 World Championship.
Its going to be more race related than the Sector and they are currently selling them at discount.
Its hard to tell what is going to happen with the production race boards. They seem to be stabilising on a tri fin about 69cm wide and maybe 5 footstraps.
Once the racing starts in 2012 though, conditions may dictate choosing different sizes of board for each event, much like they do in windsurf Slalom, where they have to register 3 boards and 6 sails for the year, so maybe smaller boards will be relevant?
If you were going to only have one board racing though, a 69 cm tri fin would seem to be the way to go, because you would get the maximum racing from it and it is like most of the 2012 racers. They also seem to handle a wide range of conditions (albeit probably with more than one set of fins, and the fins are very expensive).
Problem is, you may have to wait until they are discounted, but you would get a very high quality board then.