I would look into AI - become a technician and travel around inseminating does for a price, you could buy the semen and off you go..... you'd need some training and equipment, but you could provide a fantastic service without the possibility of disease.
I do a little outside breeding and I mean just a little. A couple of friends who I know have disease free herds. While I realize not all the diseases can be caught through breeding, certain conditions could happen that they do. I would want proof of a negative test for CAE, CL and Johnes. Also I would want a vet health certificate that would normally be required if you were going out of state or someone was coming from out of state into your state. Find out what is required for a health certificate in your state. That would give you an idea of what diseases your state is concerned with. Then you can look into it further and see if it really is a problem for goats. Also I would want to be sure that they don't have a big parasite load. All the goat has to do is poop in your yard and that buck could catch it. You could require a fecal exam done too. But you have to decide if the cost of those expenses would be worth it for someone to use your buck and still pay a buck fee.
My problem is that there are A LOT of people around me that don't care about the diseases and their goats have those diseases. They just go to a livestock auction and bring home animals that are full of parasites and potential disease and throw them into some type of paddock and give them a little hay and maybe if the goats are lucky, some feed. They are just trying to go as cheap as possible and it doesn't matter to them how many goats they lose.
I had all my goats individually tested for CAE, CL and Johnes and they are all disease free. I have to worry about my alpacas catching those diseases since they are also ruminants and can catch those diseases from goats. Since I birth alpacas for other people, I am a lot more sensitive to possible disease being brought onto my farm.
Having said all this, in the alpaca world, alpacas are coming and going from alpaca farms all the time. Outside breedings are the norm since AI isn't very successful in alpacas. But we spend a lot more money on breedings with guaranteed live births and herdsire owners do require health certificates and proof of being parasite free. We spend a lot of money on vet costs and are just used to that.
It certainly can't hurt to try it. If you are just getting a couple of males, if it doesn't work out, you won't be out tons of money. If it does work out, great, some income and you can have your goats.
I will say that I got out of alpaca herdsires because it was a pain. The males were a pain when they could smell an open female. Also, you can't control how people care for their animals. I had females that took 3 years or so before they had a live birth. Honestly, I questioned the care those alpacas got but since we guaranteed a live birth, there was nothing I could do if they wanted the breeding and didn't want their money back. There were a couple times when I just gave them their money back and wanted to be done with it. The other problem is people not knowing when their female is cycling and trying to breed a female that isn't in the right part of her cycle.
I did get my own bucks because there are few people who were willing to do outside breedings in my area and I wanted to be sure I was breeding to disease free males.
Yes, any large animal vet should be able to tell you.
I think the big thing for you is to figure out who your customer is going to be. If there are a lot of homestead type people around you that just have a couple goats and sell/eat the offspring every year so they have milk, that is a different person than a breeder of pedigreed goats.
For CAE and CL testing, it's best if the animal is over 6 months old.
You CAN have the vet come out to draw blood for you and get the test results that way, but it will cost you a lot more than if you drew the blood yourself and sent it in to a facility for testing.
When I test I send it in to; http://www.vetmed.wsu.edu/depts_waddl/
Otherwise I know another good one is; http://www.biotracking.com/ However they do not test for CL.