Check out the pics of the dagger retro kit here:
dagger retro kit http://www.nacra.ca/images/manuals/daggerboardcase%20insertion%20kit%20manual.pdf

But don't ask the price!
I have asked them to make a standard length dagger (same length as the existing one) for a lower cost because lets face it most of us are just club racing these things, not going to the worlds. If you are also interested in these lower cost, standard length daggers send me an email. dave@nacra.ca