I am not sure if understand right what you want, maybe there is no need for a plugin.

You could create some kind of template project with tickets in it.
After creating a new project, copy the tickets from the template project to the new project using the Copy function of the View Issues page.

Thank you for your reply,
in my Company, there will a lot of projects going on. Of course it wouldnt take much time to copy the tickets, but it would be even nicer if that could be done automatically :D.

I don't know a plugin for it, at least I didn't find one after having a quick look at http://mantisbt.org/wiki/doku.php/mantisbt:plugins:start and https://github.com/mantisbt-plugins

Such a plugin would have to use event EVENT_MANAGE_PROJECT_CREATE to create the tickets.

To write a hardcoded plugin that fits just your needs (all projects are very similar) should be no big deal.
To write a plugin that is able to deal with any possible Mantis project configuration (e.g. different categories, status values, custom fields, ...) is another story.

I don't see this is a feature that should be part of the Mantis core, as this is no typical use case and there is some core functionality to get it with a few clicks.

dhofma,

This is not a bug or feature request for MantisBT (you are asking for help on how to develop a Mantis plugin). I am therefore resolving this issue as "no change required".

Please use the forums to get support on customizing and using MantisBT (refer to http://www.mantisbt.org/support.php for links and further details).