I use a product called "BootIt" originating from "Terabyte Unlimited":What software do you use to create the new bootable partition?
The current version is "BootIt Bare Metal" (BIBM), but the version that I have is the previous one called "BootIt Next Generation" (BING). Neither is free (although BING was "try before you buy" when I first used it some years ago; it was a 4 week trial period before deciding whether to purchase or uninstall).
BING is quite "DOS like"; BIBM may be better (I have not used it). My OS disk is a 160GB former-laptop disk which I have partitioned into three 50GB partitions for use as OS partitions, plus a small DOS partition containing some Dell test tools. When you power-on your system, BootIt displays a menu of the partitions that you can boot. You select the one you want and press the ENTER key (I think that a mouse click works too), and BootIt boots the partition selected. BootIt also does partition copying, moving, resizing, creation, deletion, and backup to USB disk (so I use it for creating system images too).
-- from CyberSimian in the UK