I'm working on a generic API for C++ that is not tied to a specific rendering engine. If you have feature requests specific to such an interface, leave a message here, email me, or create a new issue on the Google Code page. You can find my info at http://www.dinomage.com.
EDIT: It's ready to use! Get the code at http://code.google.com/p/scml-pp/
Included is a sample implementation targeting the SDL_gpu rendering API.
I'm still interested in feedback and interface suggestions!
Currently implemented renderers:
SPriG (no GPU)