Here's a quick mockup. Please note the following features:
- PAL screen of 320x256 but only the NTSC portion used
- Enormous, busy and pointless panel at the top with multiple logos
- I couldn't bare to use the same 16 colours for the top panel, as it just looked too bad, even for those Tiertex cowboys
- I was going to cut 16 or 32 pixels off each edge to make the screen even smaller but left it anyway
- Using the Human Killing Machine palette actually doesn't look too bad in this case. Very lucky!