Retroarch, which provides a pretty graphical config fronted and file browser (more or less) to various programs that use its provided IO capabilities ("cores", implemented as dynamic libraries—mostly game console and computer system emulators, original games, and media-related programs) can run in the kernel's direct rending mode, which is, at least from the user's perspective, kind of like a framebuffer, though with 3d accelleration. If you could find a browser that can be packaged as a dynamic lib, output to a provided opengl interface, and accapt input programmatically, it could probably be ported to Retroarch very quickly by someone familiar with that process, and run without the x window system.