You can probably take the logic board out of a 475 and put it in your LC as a type of upgrade. I'm not 100% sure it will fit but it seems like it should.
I know the Quadra 605 (Another LC-style Mac) usually has enough VRAM to do thousands of colors at 1024x768. I took one VRAM card from a 605 and put it into a Performa 450 (LC III) and it had equal capability after that.

Note that you can't leave just 1 VRAM SIMM in a 605...

Click to expand...

The board will fit, but you'll also need to bring over the fan and speaker from the 475 (or an LCII or LCIII) - the original LC has a speaker/fan unit that is not compatible with newer boards.

For the record, a LC475/Q605 (exactly the same machine in a different case) can only do 16 bit (Thousands of colours) at a maximum resolution of 832x624 - the machines only support a max of 1MB of VRAM, which allows Millions of colours at 512x384, Thousands of colours at 640x400, 640x480, 800x600 or 832x624, or 256 colours at 1024x768 or 1152x870.