Here's some ships I'd like to see:
. NCC-41796. I chose that number because it corresponds to the last full day that he was alive.
With that number, it would probably be Excelsior
ENT era: Y-class cargo freighter, ECS Mychal Judge
. ECS-51133. In this case, it's his birth date. Probably ships like this didn't actually have registries this high, but I say, #)(%* that. Besides, I can't think of any other number to use that didn't shamelessly evoke 9/11.