As I wrote about last month there's a Bochs Direct Rendering Manager driver for the Linux kernel but its future is questionable due to the SimpleDRM work and other ongoing open-source Linux graphics driver activities. This Bochs DRM driver doesn't implement any 2D hardware acceleration or anything really special, it is just for virtual VGA adapters on the Bochs DISPI interface for the QEMU standard VGA and it doesn't yet support 32bpp nor mmap.
For those interested in this DRM kernel driver, Gerd Hoffmann of Red Hat published the latest revision of the code this morning. The Bochs DRM driver amounts to just under 1,600 lines of new kernel code. We don't know if it will end up landing in the mainline kernel, but it can be found for now on the DRI mailing list.