Hi, I run a site with hundreds of static pages - http://www.suan-qu.com/ .

I'd like a customisable menu to place on specific pages and thought possibly something in js for my site so that users don't have to return to the drop down every time they want a new page, even though the pages where relevant do have a 'next' link.

Ideally every category and sub category would have a separate menu. Have tried uber menu but couldn't get it working as desired. Also don't want to disturb the current margins.

The idea of a floating menu would be great as users could move it around as needed.

You might try posting this over on WordPress.org.
this wouldn't allow you to float the menus, but you could create a bunch of custom WP menus and put a new widget area in the header. Then add the menus using the WP custom menu widget and something like 'widget logic' to control which page the menu displays on.

Thanks for that