Toolbar for MS Office - VSTO tools for Office

My company designs MS Office templates in Word and PowerPoint. We need to develop a tool that will make these templates available through a custom toolbar on the Ribbon. In Word for example a client will have an option to choose letterheads and then get a list of letterheads etc. The same for reports, contracts.I would also like to add certain aspects of document formatting to the toolbar. I'd ideally like to supply the client with a MSI file that installs everything.