After quick google I found the following:
QuickstartEngine FREE but not sure if works with WP7, presumed it ebcause XNA 4 support.
FarseerPhysics Not entirely what I'm after but still worth mentioning.
Nine Looks like one of the best free ones on the list. Any thoughts?
If someone has any experience with the list I posted, would be awesome to hear what you think and if you could suggest me something else, would also be very appreciated!
Offtopic question: Anyone has any information about Unity being able to run on WP7?
Edited by HNikolas, 16 July 2012 - 04:46 AM.