Ricciardo reveals contract talks with Mateschitz

Agreed, RB is really his only option. I even think he hasn't much to negotiate with, when negotiating means that both parties need and want something from each other. Threatening to go to McLaren won't impress anyone much, surely not Mateschitz. This market is pretty transparent.
To become a second driver at Mercedes or Ferrari is not going to help him much either, if that were at all an option. I did have to laugh though, when Horner called him a "brave man" when being asked what he thought of Daniel Ricciardo considering to move to McLaren for 20M.. RB know they are offering him the best option available. "Nothing to negotiate, take it or leave it, very easy, here, have a schnitzel".

I'm not so certain, I get the feeling Ricciardo, Ferrari and Mercedes are all still posturing. Ricciardo seems too happy and plucky to me, like he knows something we don't.

If he was to be going to Ferrari, would he want to announce it yet in terms of his position within Red Bull? Would Ferrari want it announced in terms of motivating Kimi..... I don't think so.

In any case, I reckon he'd be better off taking his chances as a second driver to Vettel than be a second driver to Verstappen, which in my mind is no doubt the case, and will be even more so in 2019 when Marco's boy has the ability to take out the Youngest Ever World Champion title. Ricciardo would give Vettel a good run for his money, which would also benefit Ferrari in securing the Constructors Championship against a Hamilton / Bottas pairing.

In 2019, Ferrari-Vettel/Ricciardo. Sauber-Raikkonen/Leclerc.
In 2020, Ferrari-Ricciardo/Leclerc

You forget that Vettel dont want him newr his team. I'd like to see Ric in a good car, and I agree that being second to Vet is probably better, but I dont see it happening. Vet and Hammy have monopoly on those teams. Its more likely thah Lec will get that seat. Assuming Räi accepts reality and departs.

Though you are probably right, I am still holding out hope that Vettel does not continue to have that level of monopoly at Ferrari, because his inconsistent performances over the past 5 seasons (including his final season (2014) at Redbull) do not warrant such authority.

Vettel's monopoly aside, I really cannot fathom why Ferrari would even consider putting Leclerc into the seat so soon. Ferrari is not a team that should facilitate the development of a driver. Both drivers should have the capacity to challenge for the World Championship in order to bring home the Constructors trophy for the team. Such an expectation place on Leclerc's shoulders would be unreasonable, particularly under the unyielding gaze of the Tifosi.

I understand Verstappen's development within the top team, as given the state of the Renault engine at the time, there was never an expectation he would challenging for the WC. But surely a Leclerc move to Ferrari would be pure folly for both he and Ferrari ..... If Vettel does have that level of authority, you'd surely have to conclude Ferrari was not interested in securing the Constructor's Championship, only the Driver's Championship.

Hence my proposition, nay my hope, that Ricciardo, Mercedes and Ferrari are all still posturing, with Ricciardo negotiating with Red Bull as his downside and Ferrari using Leclerc as their supposed 'preferred' option, as part of the maneuvering that is the contract negotiation process!

In a sense Im with you, I wouldnt mind seeing Ricciardo in red. Though seeing as he is one of my current favourites, I'd not mind seeing him with an H on the chest either. :)

Generally it isnt Ferrari's style to get a junior in so quickly, and I dont think thats changed. But at the same time, Leclerc has progressed to quickly that I doubt he'll get anything out of remaining in Sauber for another year. He has already proven that he can be competitive without being involved in all that many incidents, and thats been enough to pick up Ferrari's interest further. So I dont think its a likely move either, but its more likely than Ric in Red IMO.

.....with whoever.