Now that I've read through all the posts, I understand what you're saying, Saiyu!
I've seen pre-made fursuits before; most of the time they are sold on FurBuy or FurAffinity. They usually have a free badge to go along with them, to let the new owner know about the fursona.
I think this is a great way to practice the craft of fursuit making, and an excellent way of putting your work out there.
You could even put your fursuit ads on dA or FA, see how much interest you get, and go from there. Eventually someone will commission you for their own artwork, and then you will need to draft up a Terms of Service, set up the payment plans, etc.
Pre-made suits are easier to work with in terms of your own sense of freedom, I guess--as an artist, it's easier to just put your own work out there and sell it, versus taking a commission and making a suit to someone's specifications (which can be tough, in that people are particular about their artwork and personal characters).
I think pre-mades are a great start! I say go for it!