-- Last Updated: Jan-03-13 6:31 PM EST --
Like Kim I have a Rapidfire and enthusiastically recommend it. It is costly due to the expensive materials used and the extensive labor required in construction- the polar opposite of dumping a bucket of plastic beads in a mold and turning on the heat and rotation. I really enjoy paddling it on lakes and non-whitewater streams. It's quite fast and nimble. You can read a number of reviews on Paddling.net, including mine and Kim's.
Like Carl, I have built a 14' Cape Falcon kayak (he built the SC1 while I built its successor, the F1). Have used it in many paddles on Long Island Sound and continue to be impressed with what a fantastic design it is. Reviews are on Paddling.net
I'm going to build the 14' "Petrel Play" in a class with the designer, Nick Schade of Guillemott Kayaks. I test paddled the "Play" and was impressed enough to sign up to start building one next week. It is nimble. CLC will be selling the plans and/or a kit. Weight should be about 35 lbs , depending on build quality and components added.
All 14' kayaks give up higher speeds to longer kayaks but are fast enough to keep up with average paddling groups. I would recommend the "PLay" highly for you except that it is a new design and you will have a very hard time finding one to demo for a few months. Nick has a demo in CT and there will be a few more in CT by spring, including mine. However, CT is a 22 hr. drive from southern Wisconsin (did it in one day many years ago, never again). I'll post a review in the summer after I've completed the kayak and paddled it many times.
Good luck on your quest-When discussing canoes/kayaks, my friend the late Bart Hauthaway always said "the smaller and lighter it is, the more you'll use it."