Gonna ignore the comments about flipping, but rarity is good and bad.

On the one hand you can say they only made 10, but very few have ever played a working one. Unless someone with deep pockets just likes to have rare for the sake of rare (and they exist) many will pass. At 7,500 you are asking someone to buy a broken game, that chances are they have no idea if it is even fun, for new game money. Might happen, or it might turn into your Jackbot where the starting price was too high and it scared off interest.

So, if you go swinging out of the gate thinking rare = $$ you may end up holding it. Once it sits for awhile and you start dropping the price you will still have a bunch of potential buyers scared off. They will see how long its been sitting and the number of times you've dropped the price and think *gee, guess the market doesn't think its worth near that*.

My suggestion, don't list it. Find a rare collector or gameplan collector. One might even have contacted you based on this post. See what they would offer and decide if it is enough. I bet if you take to a few different collectors who chase these things, you will get a realistic idea of what the market would bear. Everyone else is just guessing.

Look at sharpshooter I or II. Not high numbers and equally not high prices. Rare != desirable. It needs a hook of some sort. There has to be a story to it, great art, a game that was well ahead of its time but doomed. For most this is an unheard of prototype that never made it past the cutting room floor. Saying gameplan are next in line for love is just you talking it up. If they are due for love it doesn't matter. What matters is where they are today, not where they might be in two years.