[Zope] New Management Tabs and data types only with ZClasses or products

Is it possible to define new data types and to add a management tab without using ZClasses or building a new product. When not, how do you rate ZClasses in regards of stability and no long term quirks. My question is linked to the problem that I'd like to build a website out of templates which should be for flexibility very small blocks. This means the actual site(i.e. contact_html) is a folder and in this folder are other folders that contains the templates contents. But now I've got the problem to make a clean distinction between folders and folders. This means the folders that are webpages and those that are only templates. Thanks.