How about a list of paths for custom installs of Dim Pro, Z3ta+2, Rapture, SD3, PlatSample

Unfortunately, there is no standard way of directing any application to its data in the Windows world, so each vendor will implement his own scheme. Some, like Dimension Pro, make it unnecessarily difficult. Others, such as SampleTank 2/3 and Kontakt, make it easy but non-obvious. Since you don't move libraries often, every time you do it's necessary to re-figure out how you did it last time.
 
My solution is to take notes. I maintain a file that information like this goes into, along with serial numbers and installation tricks. That way, I have one place to look that stuff up when I have to re-install. I've carried the same file forward from computer to computer since the 80's, and have a hardcopy printout of it in the shoebox where I keep my backup disks.
 
Another nifty trick was alluded to by KPerry and Anderton above, and that's the use of file system links. Think of them as shortcuts like you'd place on your desktop, in that they exist in one place but redirect Windows somewhere else. This is how I tricked Dimension Pro into thinking its libraries were where it wanted to install them rather than where I actually put them. No registry edit required, and Dim Pro will happily use the new location even if I re-install it from scratch.
 
Dim Pro expects to find its data in c:\program files\cakewalk\dimension pro. You can change a registry key to point it elsewhere, but if you do you'll still have an issue if you subsequently re-install it. A better way is to fool Dim Pro into thinking it's using the default path by telling Windows that it's an alias for another location. Dim Pro thinks it's installing libraries on C: when in fact every reference is quietly being redirected to E: or whatever.
 
First, move your Dim Pro directory tree to the desired location and delete (or rename, if you're paranoid) the original folder. Then open a DOS window and run the mlink command to create a fake directory. In the following example, the "real" library folder is E:\Libraries\Dimension Pro:
    c:
    cd \program files\cakewalk
    mklink /D "Dimension Pro" "E:\Libraries\Dimension Pro"
 
After doing that, you will see that there is still a folder under Cakewalk named Dimension Pro, except that Windows Explorer displays a different icon for it that indicates it's a link. From this point on, you can reference the fake folder just as if it was a real file system location. Open it in Explorer and you'll see all your files listed as if they were really there. You can do anything in the fake folder that you could do in the real one. And SONAR and Dim Pro won't be the wiser.