Is there or are there any plans for a DOSBox library? By this I mean a program that would let you read/write processor registers, VGA memory, interrupts, and screen captures from other programs.

QEMU for example has the QEMU Monitor (http://en.wikibooks.org/wiki/QEMU/Monitor) with QMP messaging (http://wiki.qemu.org/QMP).

I'm investigating ways to run DOS, Windows 3.1, Windows 95, and Windows 98 mixed mode programs in Wine. There are lots of older programs that will use a mix of DOS and Windows code, so nothing really exists currently that can run them since Wine has either uses it's own poor native DOS support or just starts DOSBox and doesn't integrate the environments.