I have a large number of categories (152 and counting), and the category archive pages are really helpful - but I don't like the way the Category widget tries to list them in alphabetical order (I write about Motown, and my categories are individual artists and songwriters, but left to its own devices WordPress files "Marvin Gaye" under M, "the Supremes" under T and so on) - so I currently use a custom menu filled with links to the category archive pages. But lately it's been getting very, very slow to update, and now the biggest custom menu (Artists) won't save at all. I'm guessing, with no evidence, that this is because it's too big now.
How can I get around this? I could set up 26 custom menus for each letter of the alphabet, but that's not much fun. I could just stick to the standard category listing and put up with the munged alphabet. My preferred option would be to turn the category archives into pages (e.g. somehow feeding the automatically updated content from the category archives into a (hierarchically-organised) page I manually create, so the theme would automatically generate a menu in the format Artists > A > Lee Alan, or something) but I've no idea if this is possible - is there any way to do something like that?
Hopefully that makes sense, but if I'm not being clear do please let me know and I'll try and clarify what I'm talking about.