Mary,

You are not the only one to like stretch and dacron (to a certain extent) in sails.

A while ago a I posted the ideas of a Brazilian sailmaker here and his concept was that "rigid" sails are not necessarily the best solution, sometimes even for racing - depending on boat size, inventory restrictions, etc..

To the best of my knowledge, in the same sail he may use two or more different sailcloths, each stretching differently, so that the sail self-flatens when pressure increases.