I'll second Vladimir's thoughts.

Go for a second hand A. There was a carbon A with a Hall mast on sale in Newport for $3k 2 years ago, I dont know what happened to that boat, but its a point of reference. It wasnt minimum weight, but at one time, it Steve Clark's and he raced in the North American or something.

Pro's
-easy to rig
-easy to right after capsize
-easy to move around on the beach/ramp/etc
-fast and fun
-you can fix it yourself and change stuff you dont like, you can experiment and tinker.

Con's
-hard to be competitive in the dedicated A fleets - especially with an older boat
-you'll probably need to fix it yourself
-not as robust as a TheMightyHobie18

Bill