I got to thinking about your problem and you MAY have one more (relatively cheap and easy) repair option... In a nutshell and depending on the extent of your damage, you may be able to install a substantial backing plate of teak, hard mohogany or custom glass inside the hull through the damage area and secure it there to support/cover the damage area from the inside. You may have to cut a bigger hole in your hull to do it. After that, it will be a relatively easy job to build up the laminate and finish it out nice and true.
This is an epoxy job, I wouldn`t use polyesters. But if you secure a strong backing plate and do a strong and proper layup of glass and epoxy, then it should be plenty strong.
You may not need a replacement hull after all.