The betaCoin model is interesting, but I'd just make one import remark though: in this model, there's no financial incentive for people to migrate from bitcoin stable to bitcoin beta, since stable coins will always be more valuable than beta coins. This means that, from a monetary point of view, this beta risks being just a testnet++. Not many people will transfer their coins into it (it is not a reasonable investment strategy), and without much aggregated value, would it really have enough manpower behind it? If Gavin and Garzik are being fully employed to work on Bitcoin right now, it's precisely because bitcoins are valuable to lots of people. If there was a technical way to ensure people can get their beta coins converted back into stable coins at the same rate (i.e., pegging), then things could be different. But I don't see how could that be possible.
Thanks
I think the thing to do would be to define an exponentially declining incentive for early adoption into the inflation schedule. For instance, first 100k coins moved each get 1 bonus betacoin. Next 100k get 0.5 bonus, etc. Similar to how bitcoin halving works, except it's coin-based, not time-based. But ideally, you'd do it in a continuous way, rather than have steep halvings. Something like N(c) = 1 + exp(-c * ln(2) / 100000), where N(c) is the number of betacoins that the c'th bitcoin destroyed results in.