im surprised no one mentioned this but you should definitely check out a tool called winbuilder and start browsing the forums at reboot.pro winbuilder is a great tool that helps you easily create bootable winpe environments that can be loaded from usb, cd or pxe. it has tons of already preconfigured scripts to add tools, and the documentation is pretty easy to understand so you can create your own plugins/scripts. you will need to download the latest waik (windows automated install kit) first, which is free from microsoft. winbuilder will then also let you add boot entries to the list too. my personal one contains a bunch of networking scripts, the MsDART tools, passmark burnintest, and gimagex (i use it to pxe boot and image machines over the network) as well as entries for seagate seatools, hitachi dft, memtest86, and vmtce. ubcd4win is so outdated and the out of the box driver support pales in comparison to winpe 3.1 based stuff (uses the win7 driver repository). even after you boot up the machine and you can't access the hdd (e.x. some weird kind of raid setup, you can download the drivers from the mfgr site for win7 and put them on usb, plug it back into the machine and install and scan again for the hardware.
definitely check out reboot.pro