Well I seemed to have figured out the answer to my own question. I don’t know if anyone else is interested in that issue but here is what you do to mod those pesky defaults. I downloaded a free unicode text editor (the one included with WordPad.exe does NOT work with these Photoshop files, they just come out as giberish). I used Crimson Editor which works great (www.download.com has it).
Second, I opened the file in C:\Program Files\Adobe\Adobe Photoshop CS\Required\Default New Doc Sizes.txt
It will pull up the list and show you a bunch of the presets in there, that you can edit by their example. Just take care as you edit the changes (save a backup copy first). But it looks as though you can edit whatever you want. It is a bit tricky to add the rulers (as you can see by the DVD menu examples).
Personally, I think Adobe should let you create a template out of a page that is already open, that way you could easily make a page with rulers, & size, etc.