Exclude Subpages in “Parent Page”

I have a 2-part problem:

1) I’m using WP as a CMS, so I have hundreds of Pages (up to 4 levels deep). In the “write page” and “edit page” functions, it loads all of these pages to populate the “parent page” drop-down menu, which takes about 20 seconds to load, which is an eternity when editing and creating many new pages. I would like to speed this up, possibly by excluding all subpages from the drop-down menu. DOES ANYONE KNOW HOW TO DO THIS? OR ANOTHER WAY OF SPEEDING UP MY WRITE/EDIT PAGES?

FYI, I run an election site, hence the 4-level deep
i.e.
http://mysite.com/2006election/house/state/district
so page = 2006election
child page = house
grandchild page = state
great grandchild page = district
I have:

2. If I do exclude all subpage from the “parent page” drop-down menu, is there a way to manually assign the parent page?

3. Or, come to think of it, I’m not sure I need the “parent page” drop-down menu on the “edit page” function (since you usually assign it once when you create the page new, but rarely change it thereafter; and if you need to re-order it, it is probably just as easy to simply copy the content into a new page). Is there a way to simply eliminate the “parent page” drop-down menu when using the “edit page” function? (i.e. when you click “edit this” from the page)

Any help would be most appreciately. My goal is to greatly speed up my page editing (and ideally speed up the creation of new pages as well, but I’ll settle for an improved page editing).