RMIWA: DOUBLING DOWN:
SSK is right. We have a rule against it, but I also agree that it is intriguing. He seems to like it and so do I. Therefore, the odds are it will happen unless someone presents a prevailing argument against it.
It is a nice little twist that could be added without any additional work or complication. The benefit is that it incorporates one more element of the real world into the contest. That being that we all commonly invest more into some stocks than others.
Also, although diversification is a major issue in investing, not everyone is equally diversified! Therefore, if someone had 4 stocks (3 singles, 1 double), and a cash position and someone else had 6 stocks, that is not equally diversified, but not radically different either. More strategy = more interest and more opportunity to learn.
Len