Maybe a different aproaching of this post is if there is a way to restore the "arcade cabinet" code in the naomi games that were ported on dreamcast.
You know, which differences are in crazy taxy, Capcom vs Snk 2, Power stone, Spawn in the demons hand, The house of the dead 2, Cannon Spike, Marvel vs Capcom 2, Zombie Revenge, Eighteen Wheeler, Outtrigger, Ikaruga...etc
There are 80% +/- code shared between Naomi 1 and the Dreamcast, but how to find and inject the arcade version commands in the games?
Of course most interesting would be to restore the dreamcast gun functionality in Silent Scope.
And more in tone with the initial post ,how difficult is a fan port of Gun Survivor Code Veronica to dreamcast.