My
Hunter 260 requires 39'10" bridge clearance. My old
Morgan 250 required 36' bridge clearance. These figures are typical for boats this size.
Generally speaking, the sailboats that will clear a 45' bridge are going to be in the 30' long range. While such boats do exist they are something of an unusual case because they are too large to be readily trailerable (by most people's standards) yet are too small for a couple to use on a longer voyage (again by most people's standards).
The
Pacific Seacraft 34 may meet your needs. I am unsure of the exact bridge clearance but it is a smaller version of the PS37 which has 47'9". They are both slower boats with small rigs for their
displacement.