I must say that I'm interested, very interested.

Firstly, what I'd want from such an engine is that it wouldn't turn into something like the A5/6 engine. IE, something clunky, overscripted and has no source access.

Personally the feature list you've put together appeals to me and really contains all I'd want for 2D work. My only suggestion would be instead of coding your own fileformat for the packages, why not use Abbrevia instead? It's zipfile archiving and has directories and can encrypt as well.

Other than those two points I must say you've got me intrigued. If you can get most, if not all, the points on your feature list into an OpenGL 2D engine DelphiX replacement, you will probably get me as a user right off the bat.