Hi bianconeri,
Yes theres a definite lack of 3d engines for pocketpc about, apart from the more expensive solutions such as renderware and fathammer, but these are really targeted at larger more established studios that can pay the large sums of money involved for using them.
I know that dan east is developing a very capable engine that could be the ticket for you, (fantastic licensing setup) see http://www.pocketmatrix.com/forums/view ... highlight= for more info regarding that.
But as this is not yet complete we decided to make a inhouse solution to fit our needs, this has not proven to be to hard as opengl es is very nice to work with and as long as you keep your renderer abstracted you can fit in directx mobile support when it becomes more widespread.