Question: I like to have folders in my theme folder for scripts and styles, but I can't access these folders in the "Edit Themes" interface. This is problematic for clients that don't give me FTP access. Is there a way to see these folders and the files in them from the Wordpress admin section?

Answer: 
I face the same problem almost every day with our WordPress customers.

I use a plugin that allows you to edit all files of WordPress. But it is not safe for accounts on shared hosting (sometimes plugin allow edit any files on whole server).

This plugin has been removed from wordpress.org (I think for security reasons) and the author's domain now expired. I've found small review here:
<http://www.themepremium.com/access-ftp-from-wordpress-dashboard-using-myftp-wordpress-plugin/>

Below I'll post a link to a copy of the plugin. 

**NOTE:** *I haven't any relations to the author of this plugin and have not modified it. I will not be held responsible for how you use the plugin.*

["myftp" plugin](https://dl.dropbox.com/u/4075272/myftp.zip)
If a client won't or can't give you FTP access then you shouldn't be working for them. You could take the time it would take to hack the core and just find better clients.