CatMan,
You have supported your decision to shoot the bird off the limb on the basis that it's legal and it's "fair chase" because of the difficulty of getting within range of a roosted tom.
Yes, it is legal. However, legal and illegal with regards to game and fish regulations represents only a minimum standard of conduct enforced by a regulatory agency to prevent sportsmen from doing harm to the game/fish species or harm to each other (public safety). In this case, there are not enough turkey hunters shooting birds off the limb to do harm, and it's not a public safety risk. Also, a good game/fish reg must be easily enforceable so even if a game agency wanted to make it illegal to shoot a bird off the limb. How could they enforce it? The officer would have to be within sight of you and the bird to know that you did it. In this case, turkey hunters are allowed to decide whether it's ok to them or not.
To your fair chase argument, it is not difficult to stalk within gun range of roosted birds especially after green up. Why do turkeys roost in trees? To escape predators. One they are in a tree, flushing from the roost is their absolute, last escape option. You almost have to walk directly underneath him. With leaves on the trees, it becomes a situation where you can't see him until he sees you and by that time you are in range.
"Fair chase" is something we each define, but if your argument here is that getting within gun range of a roosted bird is very difficult, I think you come up short.
Finally, I read your posts with enthusiasm and based on what I can tell you are a fairly new hunter. Most of us when we got started went through a stage where blood was what mattered. We lived for the kill, and we gladly walked the line between legal/illegal or ethical/unethical to get that next one. The rush was yo much for us to restrain.
Over the last few years, I have had the pleasure of introducing a lot of new turkey hunters to the sport we love. Getting them to look beyond the kill is one of the biggest challenges I face. Yes, we are there to harvest a bird and bring meat home. What I teach them though is we each get to decide how we do that. What is legal is our first standard, but individually we should strive for a higher standard than simply what is legal. For me, shooting a bird off the limb does not meet that standard.