Yes Mint and Cinnamon are customizable. Very in fact. You just need to locate the file that pertains to the aspect you want to change. There are ways to modify the file directly or you can also create your own extension to "monkey patch" the extension or aspect of choice. For you this would be the top menu. Rearranging the applets im sure can be done by this as well. Please read on.
Out of everything I have been researching this past week there is a blog that has some of the best articles on the net on the subject.
Most of Mints "front-end" if you will is Javascript its based on spidermonkey, but uses in gnome3 what is called gjs for the engine and bindings. There is not much documentation on javascript in gnome3 for learning purposes. So if you are not familiar with javascript for application development I would start with learning spidermonkey.
Here is some starters to getting to know gjs javascript
: Or as I call Gscript (Gnome Javascript):
http://townx.org/blog/elliot/introdu...js-and-clutter
https://live.gnome.org/Gjs
https://developer.mozilla.org/en/JavaScript
https://developer.mozilla.org/en/SpiderMonkey
Ok sorry if you did not need any of that. But if it helps, great. Now to the point. the blog is:
http://blog.fpmurphy.com
http://blog.fpmurphy.com/2011/05/mor...omization.html (This is a good starting point)
In the archives list on the left, in February there is a couple posts about Cinnamon.
This is another great post that teaches the reader how to add things by making there own scripts:
http://blog.fpmurphy.com/2012/01/dua...-2-button.html
If you read most of his posts about javascript, gnome, gnome shell. You will quickly learn how to modify many aspects of gnome, Whether you are working in Mint,Cinnamon,Ubuntu,Fedora,etc.
I hope this helps.
Neqtan