I did a little digging into the VGA text mode hardware interface and it'd be possible to do proper bold and italics support by loading a second font and reusing the line drawings (which shouldn't italicize) and block graphics (that shouldn't bold) for additional styled symbols. Computing bold is a simple matter of OR'ing a bit-shifted character and, for italics, you can shift the top third one bit to the right and the bottom third one bit to the left. We used to do that in the 8-bit era when having three bitmap fonts took too much disk space.
With the frame buffer, it should be much easier.