Sounds possible but also complicated, you'd have to tap into the sender and receiver LN nodes for the custom keysend stuff. It would be much easier to buy ecash from a mint the receiver likes and send them the ecash while listening to the pod. You could do that every second and have the payment always and immediately succeed.
The podcast2.0 apps already support keysend streaming and many listeners already have a proper wallet attached to their podcasting app. RSS feeds already have fields with custom tlv values published by podcasters so that apps knew how to send. If mint supported accepting keysend podcasters would just update their RSS feeds with mint node pubkey and lock pubkey tlv and all podcasting apps would know how to stream. Buy ecash and stream is much simpler but would require a dozen apps to upgrade which is not realistic.
Minting ecash is an interactive process where someone needs to interact with the mint. In the case of a kind of "bridge" service, it could mint p2pk ecash for the receiving users (a bit in direction of npub.cash). You can avoid all that if the sender can talk to the mint directly. I think nostr:nprofile1qqstzfq9x083h745pwtmrhg7dlr8njel4ds0mzvj75u8hx0sg8tp0vcpzamhxue69uhhyetvv9ujumn0wd68ytnzv9hxgtc3vsuae did consider using ecash directly because its simplicity.
Keysend arriving to mint's node would show up as a paid auto-generated invoice (instead of it being created using /mint/quote) and then mint could issue tokens locked to pubkey from tlv and publish to relay. No interactivity needed. Or am I missing something?
I see where you're going with this. Yes, with a custom extension of the protocol, a mint should be able to do this. It's unusually that the mint produces wash by itself (it's an interactive process), so the mint would use something like their own wallet to do so. This is usually a no go for privacy reasons but since it's a locked token anyway and the receiver's pubkey will eventually be doxed upon redemption, the mint could mint those tokens itself. I still think this doesn't embrace the potential ecash could bring to the whole process though, it would be a better strategy to make few LN payments but many ecash payments. But if it's worth considering because of existing support for keysend assuming it's easy to extend (tlv including relay+receiver npub), it might be worth exploding.
*exploring