Theme/Plugin Editor for Multisite?

No, because the themes and plugins are network wide.

You can use a plugin like safeCSS to let them edit their css per site.

I have read somewhere about ways around this, but this was for the older versions before wordpress 3. I am sure something must exist now to do this as well

You understand that it two sites are using the same theme, they can BOTH edit it, right? And how that MIGHT be a bad idea?

Ditto plugins.

While the theme editor and plugin editor DO exist in the admin area, they were designed to be used for light editing or in cases where a control panel didn’t exsist or for when you just were not able to ftp files.

You know if you drop a wrong character in a plugin file that you’re editing you’ll blank out your site?

Now lets suppose user A is editing a contact form.. that is also in use on userb’s site.

Yeah. mondo problems.

If you want users to edit plugins and themes give them their own separate installs to blow up.