I think it would be interesting if someone tried a fork of bitcoin with the same speed-of-generating-new-bitcoins-graph, but with no cap at 21 million btc. Instead, when the 21 million is reached, there will be an inflation of 0.7 % per year. That would mean that the money supply would double once every 100 years. That is an acceptable loss from a currency user's perspective, and would add any benefit(s) an inflationary currency arguably has. I could totally live with my savings halving in value once every 100 years, if that sacrifice boosts the usage of the currency, prevents hoarding etc.