I thought about the 5x thing as well. As for > 19k bonus, the next 'step' up is to do the factorial bonus thing where it ramps up instead of being shown directly with a light bulb or 2 or 3. This gives you 55k with all the lamps lit. (This is the way fathom scoring works on each color). I did that in the past to Trident and believe it or not, it was terrible. Was too crazy long to count down the bonus and changed the tenor of the game too much. (The multiplier went up to 7x as well, or maybe I did 12x? Have not had the game for over a decade now so details fuzzy even though the software is still available).
I don't really think stars would need too much tweaks but these are all good ideas. We'll see how much time I think I actually have to implement any of this of course.... anything would require a minimum of jumpering the mpu board to 2x2732 for more room.
Of course, I'd add a better attract lamp show.
I've often wanted to implement the Lost Vegas rule of plunge softly, go through the spinner as your first switch, then hit <something> for increased scoring. (Within a short time period). (LV was to be a dolly parton conversion kit in case you didn't know).
With a complete rewrite, the need to have at least one star lit could be eliminated. The stock software just doesn't know what to do when there's no star lit so it just crashes.