Are there any hosting-companies that provides (possibly exclusively) hosting for Tor hidden services sites? Or is my only option to set something up myself on a computer I own or rent?
you can not trust to anyone, they can be honeypot and arrest your users or they can steal information about your users or bitcoins of your users. the best is to follow schema of some drug dealers: they keep drugs at some poor man who will keep it for monthly money. you can do the same with server. I looked many hosting and data centers, believe me, even if they accept bitcoins, they record your IP address and they demand copy of your ID. simply, they must rent server in data center and then they resell it, it means they had to give their ID and if you do anything forbidden with server, he will be arrested because he rented servers with ID. you can also pay some poor man to use his ID to rent server for you but you must pay him good. there are people who will do anything for money and later they will have to run from cops. who needs money urgently, he will do it. you can also place serve rin your home, but again, your ISP can decide that you can not use tor. not all ISPs allow tor. by the way, you can also rent server and provide tor hosting to the other people :)