"I don't think this could implement a blockchain, persay -- as the current hashpower is required to maintain one. The coins would have to be secured and verified some other way. "
This is a non trivial issue. I mean if you simply explain it away and then don't come up with a solution it is DOA. The system needs to be secured by something and currently every distributed implementation is secured via massive computational power.
That doesn't mean coins couldn't be redeemed for time on the network. Bitcoin doesn't currently implement that but unless everyone "redeemed" a lot of coins at once there is no reason the network can't do both. In essence you need computing power. You redeem one xCoin via a transaction and it gets allocated via the network to a node. The node does the work and gets x. You get the results. The issue them becomes avoiding counterfit work.
What if I do your "work" and simply return all zeroes. There are potential solutions but those solutions add more problems. It is an interesting idea however starting with "the coins would need to be secured another way is usless unless you have another way".
A more useful academic exercise is:
1) I know distributed computing power can secure a block chain
2) I know some % of that can be siphoned off to do other works (with compensation) without significantly increasing the risk to blockchain.
3) Can I somehow come up with a system which uses 1 & 2 to fix a coin to some amount of usable computing power?
I was actually just thinking that perhaps, when the demand was low for computational power, the network could be securing a chain -- or perhaps up to x% or total power will always be creating the chain. As for verifying work, you would have to run the "official miner" which would check itself against the other miners on the network, or you could have two separate miners work on the problem, and compare answers...those are very good questions, keep them coming, please, as we work this out.
USD, for example, started as backed by something (gold) and are now backed by millions of users and the US military.
USD is backed by taxation system. You need
USD or you will go to jail.
Yes, and they send you to jail with the military might they possess.
Sounds really interesting, but the potential for malicious use of the rented power would surely be huge?
Yes, it could be used for evil. But so can lots of things -- I don't think that's a reason to not pursue it.
This idea is something I'm still working on -- any suggestions are welcome, criticisms etc.