LinuxBSDos.com posted a triple-boot tutorial with Windows 7, Ubuntu 12.10 and Fedora 18 on a single hard disk drive
To Triple-boot Windows 7, Ubuntu 12.10 and Fedora 18 on a single hard disk drive (HDD) presents a different set of challenges than dual-booting any two of the set on same HDD. This article presents a step-by-step guide of one method of how to install such a system.Triple-boot Windows 7, Ubuntu 12.10 and Fedora 18 on one HDD
Note that with the cost of disk storage as low as it is now, it is recommended, when attempting to set up a multi-boot system, to do so using more than one HDD. Not only is it relatively easier to set up, but it solves that little problem of having a single-point of failure that a 1-HDD multi-boot system presents.
That single-point-of-failure issue is the sole case, and a very important one, against setting up a multi-boot system on one HDD. Aside from that, nothing prevents you from installing as many operating systems on one HDD that it can hold.