I have to say that I don't find the proportions of your boat unpleasing.. I think the designer did a reasonable job.
That said, trim and stripe treatment as you suggest (and JRP agrees) can be very effective. Another thing to try perhaps (do this on paper first) is to try a wider, bolder cove stripe and see if that visually makes the house look comparatively lower.
".. there is much you could do at sea with common sense.. and very little you could do without it.."
Capt G E Ericson (from "The Cruel Sea" by Nicholas Monsarrat)
1984 Fast/Nicholson 345 "FastForward"