Here's a listing of Portsmouth rating system for inshore centerboarders which will define the relative 'speed' potential of currently raced (and formerly raced) 'small' boats: Centerboard Classes
& (inactive) Centerboard Classes-Inactive
For 'speed' and versatility, ... and for sailing in relatively 'flat' water, Id consider an MC Scow, an M16 scow, or a 'bendy mast'/tunnel hulled M20 scow (with ~35 'control lines' - a 'handful' for a single hander but can be done); however, with 'scows' they need to be 'heeled well over' and thus the need for some wind to be able to 'fly'. Ive occasionally pulled a water skier with my M20s !!!!! .... also: Thistle, 420, Flying Dutchman, 505, GP14, etc.
With the current continued demise of small sail boat racing, if you look hard, you might find an unused one of these 'pocket rockets' sitting in a driveway, etc. and that may 'go for a song'. My first M16 scow with which I won a 'lot of pewter' was a 'find' from a 'junk pile'.