I would offer a daily dividend of .25% of principle ($1.5 out of every $600) that would be paid out of my non-bitcoin related activities (this would be paid to encourage people to remain in the fund and to ).
I am able to minimize bitcoin volatility the way way I do through stock trading: selling call options (a covered call) & market timing. Due to bitcoin's abnormally high volatility selling options can be very lucrative allowing you to make money in any market condition, including declines.
http://www.investopedia.com/articles/optioninvestor/08/covered-call.asp
For example, using Black-Scholes option pricing on bitcoin with a $700 strike, $700 present price, and 1/2 year time until maturity, and 200% volatility. Such a contract is worth about $360. By selling these contracts I am able to collect guaranteed $360 per bitcoin at the end of six months even if bitcoin does nothing. I would only lose money if bitcoin falls below $350 after six months.
http://www.mystockoptions.com/black-scholes.cfm?ticker=&s=700&x=700&t=.5&r=.001%25&v=200&calculate=Calculate
what exchange buys and sells options? or are you just going to start it yourself? lol