I too like the flattr model, where you allocate a certain budget of points on a particular cycle (monthly? individually configured period?), and perhaps if you feel like it you can go and manually re-organise your points distribution before the cycle transfer date.

I'm unsure about placement of kudos buttons - user head pop-over? user profile? posts? comments? Everything? Hopefully they could be optionally turned on/off?

Then there is the question of opting in and out of kudos and/or points aspects - some individuals clearly want both, some one and not the other, and some neither. And then there's the extra variable of whether kudos and points transfers are anonymised or not.

I'm thinking that users might be able to opt out of seeing kudos and/or points, but that could lead to distinct oddness if some users are able to see kudos and some aren't.

I think perhaps the only way this would work is if kudos ratings are invisible except between sender and receiver. So if you have a comment/post/whatever that's piling up kudos, the only person that knows it is yourself. And if you're being sent kudos anonymously, that's all you know too. As a kudos sender all you see is whether you've given kudos or not, and you don't see anyone else's. That possibly avoids some of the weirder "gamification" aspects of a kudos system.