Please have a look at this article.
http://ribbonworkbench.uservoice.com/knowledgebase/articles/76681-hide-a-standard-out-of-the-box-button-based-on-a
in general the easiest way (without single line of code) is to create new Security Role which will have an access to entity which you're not using or new entity. Then you can setup that anyone who will have an access for specific action (like Delete) for
specific entity (like Quote) can see this button. Rest will not be able to see it.
It's working.
KG
My Dynamics CRM Blog: http://bovoweb.blogspot.com