Mike,
Mainsail:
18m2 + half mastarea
Dacron/Mylar
maste height max 9850mm above mainbeam
Spi:
Weight class 1-2: 23m2
Weight class 3: 25m2
Jib:
Weight class 1-2: 4.15m2
Weight class 3: 4.85m2
Hulls:
max length: 6200mm
max width: 2600mm
material: polyester
Daggers:
max 7kg
Rudders:
max 3 kg
Crew:
Class 1, 135kg tot < 150kg (including correctors)
Class 2, 150kg tot < 165kg (including correctors)
Class 3, 165kg or more
Security equipment:
1 paddle, min length 1meter
1 towing line, min 15m long 6mm thick
1 righting line, min 6m long 10mm thick
2 PFD's (dont understand what "op lichaam te dragen means". Dragons who like to drink tea perhaps..)
1 compass fitted to the boat
Dont forget your measurement letter..
Thats all there is there.. (I hope, perhaps Wouter can correct me if I have done any mistakes translating)
Sorry, I'm having too little time to keep up with my own class work. So I'm not checking this data, you are on your own guys.
Wouter
I have recieved some feedback from both designers and builders. They suggest a range from 125 to 135Kg's as minimum weight. That weightrange is achieveable for a 20 footer with a jib both for manufacturing and homebuilding (in plywood if need be)in their opinions.
I would suggest a minimum weight of 130Kg's, based on that input.
Another issue, well debated earlier, is the 10 foot beam. It's viewed as an detriment for the average sailor Joe, not beeing able to put it on a regular trailor. Options are either a tilt trailer, disassembling, or some sort of folding/sliding mechanism. Personally, we use 1 hour to tear down our boat for travelling, and two hours to put it together again. We can leave the boat with the mast up at our club, so we dont rig the boat every time we want to go sailing.
Having sailed a cat with a 10 foot beam for some years now, I would not consider a high performance cat like what we are discussing here with a 8 foot beam. Even if it's more convenient when you need to trailer the boat around.
If assembling the hulls/crossbeams/trampoline platform is to much, I seriously suggest a kind of tilt trailor. There are many types of tilt solutions, but one of the best one I have seen used the area under the boat as a gear-storage/camping shelter. It looked kind of like a scewed metal tent, provided great storage and a place to sleep if need be, plus, I think it helped with the aerodynamic problems of trailering a tilted 20 footer (crosswinds and meeting trucks).
2 PFD's (dont understand what "op lichaam te dragen means". Dragons who like to drink tea perhaps..)
"to be worn on the body", although I quite like the idea of a tea-drinking Dragon 
Rolf, suggest you go with 10ft beam, or even unrestricted. If guys don`t want the extra rigging time or tilt trailers they can go with 8ft beam and add racks like skiffs, the F16 rules actually allow for this as well, if the boat is less than max. allowable specs (2,5m)you can add wings / racks such that the boat width plus one extended rack is at or less than max. beam.
Would be fun to see 20ft cats with massive rigs and huge racks out pitchpoling all over, make good tv coverage 
Right Steve, to be worn on the body of course.
Racks are a good idea if trailering is a large problem! Are they included in min. platform weight on the F-16's, or are they 'extra'?
I would like to limit sailarea, but let the 'daredevils' put extra high masts on their boats if they want to. I was considering putting racks and a Tornado rig on a 16 footer once, but never got around to it (in hindsight, I am glad I never did. Would have been a real pitchpole machine).
1.3 Boat weight
The minimum weight of the boat ready to sail, excluding non permanently fitted wings, is fixed at :
1.3.1 Singlehanded mode (cat rigged with gennaker) : 104,0 kg. (= 230 pounds)
1.3.2 Doublehanded mode (sloop rigged with gennaker) : 107,0 kg. (= 236 pounds)
So min. weight excludes the wings / racks. Just have to make them really light then, eh ??
(Above from F16 class rules, not to confuse F20 interested parties, in answer to Rolf`s question.)
The boat Wouter described is already out there, known by the name of "Super Taipan 5.7", right Macca?