Hi Graham....
I like your idea to "share a trailer" but I wonder if you have any experience with trailers and trailering such a big boat as the Parker 27? Maybe your 26 is lighter and easier to deal with but I have lots of trailer experience to share with my Parker 27 "The Happy Seal" .
My boat came into the USA in 1989 on a platform cradle which I figured will certainly work with some wheels under it....wrong! I visited a trailer builder (Continental) in Miami, Florida. Their engineer came to see the boat..it's weight and size AND the fact that I will use this trailer to move the boat between Florida and New York....AND float the boat off.
Well I ended up with a 36 foot trailer with HUGE bungs (10 x 10 inches) running length wise (no cradle), dual axle, dual brakes and lots of maintenance head aches for the next 10 years. ..Oh and I forgot to say that I moved this monster with a Chevy Suburban 454 cubic inch engine (another huge cost). Whenever we drove to Florida, we got about 9 miles to the gallon, the road hills really needed downshifting and many stops to check and grease everything. I blew tires on two occasions going 45 miles per hour..scaring the pants off me and my partner.
The worst problem came as the brakes fouled...usually every second year because of saltwater, rain water and rust. The trailer was only used a few time per year and also became a storage problem. Finally, there was a small "road legal" issue...it seems that in the USA, our laws permit 8 foot wide loads..anything over that (P27 is 9 feet wide) requires a special sign and permit..for each state one crosses.
ON the bright side, I did move my boat to/from indoor storage ( about 25 miles) every winter in Upstate New York. The trailer usually did help a lot with keeping the P 27 in such great shape and certainly easy to clean and service.
Well to sum up, a great idea (trailer sailing) may require a lot of effort, and cost but if enough guys can help keep up the maintnence...go for it.
ME?...I finally bought a property here in Florida and now, my boat is on a lift in my backyard and NO MORE WHITE KNUCKLE RIDES. LOL
Good Luck, Marv PS: I have some pictures ..which I hope I can post here if someone tells me how.