I own a computer business too and can certainly understand wanting to make more money - especially recurring revenue.
What you are proposing sounds like a lot of work to me and I wonder if you have given sufficient thought to the risk you will be assuming for your clients. You will be responsible if they need their data from the offsite location, so above all you had better be sure that you really have it.
If I were you, I would look for solutions that will do what you want, but don't provide their service to the general public. Many of these services allow you to brand it with your logo and your service name. That will also allow you to use data centers that are not in your geographic area without you having to worry about the logistics or the details of the hardware configuration.
I hope you don't think that is a 'just let someone else handle it' answer. I believe that while there are a lot of solutions, it has not been widely adopted by small business, so I think that this is a market that has a lot of potential.
Unfortunately, I don't have a product recommendation that will meet all of your requirements. We use
eFolder to backup up critical data from workstations and I do believe that they have multi-platform support. We have branded this under our name.
For server backup, Windows only, we are using the
Zenith Backup and Data Recovery solution.
If you are really interested in providing Business Continuity services, check out
Xilocore. I just talked to them at CompTIA Breakaway and this is an impressive product at a reasonable price. If your client has a complete disaster, they will virtualize the servers and have them back in business via the internet very quickly. They do have multi-platform support as well.
Be aware that this is a C Level sale - you are selling insurance to the business owner and you will have to have a business owner to business owner conversation to sell it.
We have been offering
remote backup services to our clients for a couple of years and have tried several solutions. My experience tells me that I want to give up a bit of my revenue to let someone else share the risk. The margins are still very good, and once we have the setup completed, it is very little on-going effort.