I have one for a Hunter 34 that might fit
I have a mainsail cover for a Hunter 34 in good condition.  It is a royal blue with a little bit of dirt but otherwise in good condition.  I replaced it for two reasons:  1. It did not match the other canvass on the boat.  2:  I replaced the main with one of very heavy stiff material that requires a large girth sail cover when flaked.  What dimensions do you need?  I could let you have it for the cost of shipping.