Fish tales, seems like a great idea and do not see why it couldn't be done. Great way to add additional storage also. Wish I had a Marlin nearby to take a closer look at this. I would need some good pictures and accurate dimensions to move forward on this. Need to see where to make room for the box to mount and have the companion seat mount on top of it. I'm sure we could get creative and it would come out great. If you would like to move forward on this send me your contact info and I will get you in touch with my father.
Back in 2006 the up charge was $650 additional (plus helm seat chair delete) for it. After seeing how it was built, I'd go with a proven helm seat any day of the week. Can't believe how some of the stuff us built on these boats. Looks nice covered with all the fancy stitching and stuff, but under the quality isn't there IMHO.