We have done that a few times already this year... I was actually thinking of moving the 3 servers from the ISP to my house. But the commercial internet to my home and no backup power would have almost cost us the same. Plus we tried moving off of non premium bandwidth before and you can remember what a mess that was.
What the OP says about operations costs for the servers is correct, but he not factoring in many of the other costs that we pay monthly which we have been over before. For example last month we renewed our cpanel licenses for a year at a cost of $425 per server.
I am not offering to host your site though I probably could put it on one of my lesser used servers and unless you are getting thousands of connections per second, it probably would not be a big deal. Or, I can put you in touch with a great data center where you can get a very powerful server for around a hundred bucks a month, tons of bandwidth and pretty much NO down time what so ever and if any, very very rare. I've never seen any with the one I would suggest at least.
As mentioned in my first email, you can get a hefty quad processor, 32GB/1TB HARDWARE server (not a vps) for a little over a hundred bucks. You could have a 1000Mb/s connection and 15TB per month. There is not much chance you would use that up with this site. Even if you have a ton of services running on the server, it's mainly memory which you care around, CPU's will hardly be used for the web site and many httpd instances could be waiting for hits without using up much memory. You would still have lots of memory to run MySQL (assuming you are using a LAMP setup) and could turn off any unneeded services of course.
I can't factor in all your costs because only you know them. What I have learned however is that much of the time, the costs are higher because the operator isn't all that interested in doing things right, they just want to do it their own way. In some cases, they simply don't care that much to save money because it's so much fun to brag about costs and complications than to actually simplify it AND saving money. Not saying you are doing this, just saying that much of the time, many costs can be eliminated but it often takes talking the owner down to earth in what they believe they need vs what is actually needed.
I'm not sure why you need three servers to run a web site but I've consolidated tons of very complex setups into simpler solutions that cost much less to run. You could still have a low speed connection at home or elsewhere if you wanted a little redundancy or off-site backup and at worse, if the data center ever went down, you would have a low speed backup which your users would appreciate.
I'm guessing you don't need a mail server so sendmail or php is all that's needed for outgoing mail since incoming is always on the site itself.
I'm not sure why you are spending money on cpanel for in house servers if you're not hosting or something along those lines so again, only you know that but usually, panels are used for remote access on shared resources. If you aren't sharing your resources, there are MUCH cheaper (FREE) alternatives such as webmin and countless other ways of remotely accessing your resources and of course, ssh and tons of other command line tools.
As for your radio show, same thing, you could easily either use the same server or rent another server and simply send your stream to that server from a low speed connection and users would connect to that high speed server instead.
Again, not knowing your setup, I can only guess and assume but I've done lots of this kind of work. I've also had to consolidate my own data centers many times including ending up building them in my own home because it no longer made sense to rent the space when I could get everything I needed at the house. With generator, huge battery arrays, multiple connections in multiple formats along with having multiple providers, I was running over 200 CPUs and huge fibre channel and other types of RAID storage arrays right from my basement. Of course, my power bill was some $800/Month on good months but all of it ended up being much cheaper than renting space and maintaining it.
There are always ways of saving money and running a web site should not cost anywhere near the numbers you are talking about based on what I know at least.
I'm not looking for money and I barely have any time to help you but I've always found good help from this site and would be happy to offer what ever suggestions I could via email perhaps if you are interested and willing to give me the information I need to help you.