Everything to do with CNC is expensive (he says looking at a quote for a new CNC mill that is nearly $100,000!)
Back in 2000 (so 14 years ago) I did a one off CNC gun body for a friend that costed out at around $3,000 of work. That included the CAD and programming, but not the machine time. It was run on an X-Mag blank on AGDE's machine so they didn't charge the machine time as they were selling the gun, and the guy buying it was a good customer of theirs and friend of mine.
The going rate for CAD for a paintball gun body design goes from anywhere from $500-$15,000 depending on who it is doing the work and who they are charging. That's just the CAD. Back in the early 2000's when I was doing Intimidators I would charge $2,000-$3,000 for a new cosmetic gun design.
Any time I have used someone else's CAD (no disrespect meant) it's been an issue and I have had to fix things. Typically if you aren't doing the checking until the first one is cut you have wasted your programming time and your machine time if something is wrong, and your first body. Maybe a fixture too. So you check it up front the best you can, but that takes hours of work. It's a trade off.
A small custom shop that is good enough to do what you need on a one off body is going to be $125+ an hour. Maybe significantly more. Not unusual for a great shop with advanced equipment to want significantly more. I personally would never touch a project on a one off body that I couldn't replace.
Any time I have cut even a custom engraved body, it's never taken me less than 4-5 hours. That's programming, set up, toolpath verification in air, running on a scrap body (if possible) running slow on the actual body with offsets so to not fuck it up, and then adjusting depth to cut it nicely, sometimes running the engraving 3-4 times to get it perfect. On several occasions with 4th axis or even 5 axis engraving I have screwed up slightly, and enough that it scrapped a body
That's on gun bodies I designed, I made, and I have fixtures for.
I can't charge for that as it's just too expensive, so I only ever do it for friends or as a gift, and I pretty much regret it every time I take on such a project. It's always more of an issue than it should be.
And then there is the opportunity cost of not working on a production item, and since the mill is running non stop right now (hence why I have quotes for more machines) the cost of lost production as I am taking the time to make a one off.
Obviously the point of the machines, and the software etc. is to run a viable business from them.
I have many people ask me to run "one off's" or something custom or to "just go wild and do whatever you want" on a single body, and the reality is after costing it out and working out the value to the company, if I am not charging around $15,000 for such a project it simply doesn't make sense to take it on, and I should be working on my other production items instead.
That sounds like an insane number, and it is, but then I look around at the $500,000 I have invested in what I am doing here, and the importance of keeping it all going, the insane costs of having a business and overheads, and that is the reality of a choice to do a one off instead of to run production, and to work on more products that I can realistically sell 100+ of.
There are people that will charge you far less, and do a great job, but they are typically doing it for fun, on someone else's equipment and not running it as their full time job/business.
As much as I would love to run more one off jobs or individual custom jobs, I know that I couldn't survive as a business based upon what the market would pay for the work.
And that is why you can't/don't find many companies willing to take on the jobs.