In theory if enough additional money is thrown in, almost anything (as long as it exists) can be bought with the lesser game as a "trade in".

I'm sure even the "it's bolted to the floor" crowd would sell if the number is high enough.

I was thinking this was going to be along the line of continuously trading up with no cash.

Step 1: Trade Surf n' Safari for X

Step 2: Trade X for Y

Step 3: Trade Y for Z

Step 4: Trade Z for (Dream Game)

Where each step is increasing the value. *That* would be interesting to watch happen.