Constructing such a general urlrewrite an using it to automatically store stuff on steemit is not a problem to do.
The issue is (as you know) the content delivery. BUT, we could build a network of IPFS content delivery networks that can be instantly replaced or load balanced if we had the IPFS-hash already. If steemit.com allowed to upload pictures, you would have that hash and could seed the file in the IPFS network.
This is how I think it can be done:
- User uploads content on steemit.com (similar to ipfs.pics)
- Steemit.com puts the stuff on IPFS and merely uses the IPFS hash in the post
~[ipfs:HASH] - People browsing the steemit.com page will see an
<a>tag withhreftohttps://mirror-providerA.steemit.com/?=HASH - Steemit could pay people for delivery (though it requires some trust as the deliverer cannot know how oftern you showed their link to the users)
Well, incentivise people to host IPFS nodes is not easy (as you know) .. no money involved :(
I guess you could ask witnesses to host such nodes. They already kind of have to host a seed node, why not ask an IPFS node from them too? At the moment, the pay largely compensates for it. More generally, I believe that a network supporting a DAO will need various types of specialized nodes to efficiently provide the functionality offered by the DAO, and this should be payed by the network itself. We already have witness nodes, seed nodes, now IPFS nodes, I can see more popping up in the future. I'm sure we can find a way to pay for all of them while avoiding abuse / theft of funds at the same time.