Have a good relationship with your local auto body shop guys? The replacement top cover I got on eBay for the dented MX mentioned above... itself had a dent in the pentaprism area, an easier spot to fix, no corners.
I took it to my dent-fixer (to whom I'd given way too much business) and he used his skills to pound out the irregularity and spray it with matching semi-gloss black enamel. Looked like new, no charge!
This may be a possibility for you to look into...