I would reconsider the Mudbuddy. I own a Excel boat but would never consider a Mudbuddy. Everything I've ever read about them is negative. Check
www.mudmotortalk.com.
For the money your looking to spend I'd HIGHLY recommend spending a the difference and getting either a Prodrive or a Gator Tail.
http://prodriveoutboards.com/index.php/motors/models/
A Prodrive 25 HP with neutral no reverse is $5270.00 brand new. With Manual reverse it is $5475.00. This motor is 10 times the motor of any you mentioned. AND it has electronic fuel injection. If you ever decide to add reverse it a easy add on. This is what I would get.
http://www.gator-tail.com/motors.html
If you don't want a Prodrive then a Gator Tail with neutral and no reverse for $5750.00.
If you buy one of these motors and ever decide to sell it you will have no problem selling it for a good price. The Go Devil Surface drive or the Copperhead will take a little more time. The MudBuddy will likely take much more time. Whatever you do DO NOT GO NEAR A DIXIE!
Good luck.