Maybe you should reward investors based on their bitcointalk "activity" level. If it really is a bitcointalk coin, then those who have been here the longest should reap the most rewards, right?
Sounds reasonable. It's pretty easy to make 100 accounts with few posts I believe, but it will be almost impossible to create few active accounts without spending time posting here))) So, I would establish amount of member's stake based on his activity, registered date etc. Just made account with few posts - you'll have 1 coin. Hero member - 10,000 for example. That wiill be fair.
Anyone who created an account before the announcement of this thread would be given coins, no one who made an account later!