twin handed dinghy

Contact class associations and try and arrange a trial sail of a few boats to see what you get on with (Ovington and RS will almost certainly oblige, Try contacting Andy at Wet and Windy in Bristol for details about Buzz).

Don't discount some of the more traditional classes

Your list suggests you have a reasonable amount of experience, bear that in mind, you may want a challenge but too much time spent swimming doesn't help you learn and I wouldn't advise buying a boat you can only manage in sub 10 knots, most fun is often blasting in 17 - 20 knots.

garry

A 29er is what you want, 3000s are nowhere near as fun!  You hardly move in a 3000 when there is less than 10 knots, great fun in a blow though, but its never a blow when you want it!

Alternatively, a 200/400 could be a good bet, you arent particularly heavy at all... you wouldnt be a particularly heavy 29er team for example.  LDC often have boats in that they want to clear so a cheap decent 200/400 may pop up, just give them a ring.

The Buzz, well its never stood out to me as a class leading boat, looks a bit clunky for a trapeze boat.

I would say if you have a river to sail out of then stick to hiking for the moment, saves a few splashes! Something like a second hand 200 is fast enough, easy to handle and you could sell it on for the same price you bought it at probably with a bit of TLC.

Same with beaches like stokes bay, its tricky enough launching lasers into a swell, trying to trapeze into a swell from the beach wouldn't appeal to me...