My own favoured epitaph is a line from a Dylan Thomas poem. "The force that through the green fuse, drives the flower" It sort of seems to me to say that you're still doing some good after you've gone. Of course being a Scot I should be choosing lines from Robert Burns, and there are too many to name, but "A man's a man for a' that" springs to mind. Whatever Mortie, I'm sure that the appropriate words will come to you eventually, good luck in your search.
Failte.....Giok