Hi,
I am not in the position to comment on what would be good for the network, there are others more knowledgeable - like yourself. There's not much to add to your remarks. Having said that, I can comment on what I would change for me.
I am currently providing a fast exit node on a colocated server I already was running. It's using spare traffic and bandwidth. Current limitations are based on the policy "use anything that's left, as long as it doesn't cost me any bucks". I am more than happy to spend time and effort in running relays, but I don't have the budget to pay for more.
- Should we fund existing relays or new ones?
I would be able to help out with both. For me there would be at least three scenario's.
1) If there's reimbursement for (additional traffic on) existing relays, I would be able to add more traffic a month on my current relay. I would increase the limits on bandwidth and traffic. That way, an existing relay would be able to do more traffic.
2) If there's reimbursement for everything that is needed to run a relay, I would be able to add a new server. I would find other ISP's that sell VPS's or, when I would be able to get a new box, I could add another one at my current ISP. That way, a new relay would be added.
3) If there's reimbursement for even more, I would set up a non-proft foundation running multiple nodes. These nodes would ideally be spread amongst a couple of ISP's. That way, I would be able to add a couple of new relays.
More generally, we need to consider sustainability. Our current exit relay funding is for a period of 12 months, and while there's reason to think we will find continued support, the Tor network must not end up addicted to external funding. So long as everybody is running an exit relay because they want to save the world, I think we should be fine.
Given the above scenario's the sustainability largely depends on the scale. For example, when I would be reimbursed for the additional costs of the additional traffic, I can easily back down after 12 months. When running a foundation it would be more difficult to simply quit just because the sponsoring comes to a halt. On the other hand, a foundation would be run by multiple people, and as long as there is money to cover the costs of the relays, it would be a lot more stable than a number of smaller nodes.
- How do we audit / track the sponsored relays?
How should we check that your 100mbit relay is really working? What do we measure to confirm its capacity? To a first approximation I'm fine assuming that nobody is going to try to cheat (say, by colluding with an ISP to write legit-looking invoices but then just split the money).
And what happens if there's doubt about the node someone is running? For a starter, maybe a solution would be: individuals are reimbursed a limited amount only, where larger amounts is available to legally registered foundations.