How might an "off-blockchain" payment system work for Peercoin?

I was wondering how a theoretical off-blockchain payment system would work for Peercoin. As Peercoin isn’t designed for micro-transactions, would it be possible to develop a system that works separately from the Peercoin network, allowing high numbers of transactions at low fees without bloating the Peercoin blockchain? One example I can think of so far is how the “tip bots” work on reddit. Also, would such a system have to be centralized or are decentralized options possible? I know another option is just using a different cryptocurrency for micro-transactions, but I think the average person would prefer only having to deal with one currency for all their needs.

Basically you privide an on-line wallet/account for people to spend/deposite.

It would be similar as gold backed usd dollar was.

So you would pay peercoins (gold) to third party like some corporation or bank, government etc…, and in exchange that third party would give you their centrally controlled currency which would have their name e.g. edollar or amasondollar etc… That edollar would be backed by peercoin meaning that at any time you can return them their money and take back peercoin.
While you hold their money you could cheaply send that money to others back and fourth as you are using centralized third party not peercoin network.

Risk would be like with us dollar, that at some point that third party which is holding your ppc might default on their promise and you couldn’t take back ppc. That what happened to gold/usd. So for large sums and long term saving that wouldn’t be good idea but for quick cheap transactions that would be very useful.

Currently there are no solutions designed that are decentralized and horizontally scalable (supporting high-volume transactions).

Secure transfer of private keys might be a possible solution to the problem of centralized off-chain transactions.

Had I more time I would have studied Open Transactions because I think (think, not know) that might go very well together with Peercoins.

Lets imagine Neo&Bee spawning new branches in other countries and promoting Open Transactions. That just might, if my reasoning doesn’t fail me here, create a lightweight infrastructure which crypto currency “external” businesses such as banks, could connect to. I my mind this would create a secure decentralized ecosystem open to well established institutions, opening up this whole new thing to mass market adoption without many of the scaling issues associated with that. Just my 2 Satoshis.

CapR I’m a bit skeptical with that transfer of private keys off-chain.

Basically bottom line you would have to trust some device? If that is true then it’s not much different then those physical coins, guy who made them can potentially abuse that power at any moment so we are back to trusting third party again.