After all the disasters and delays that plagued The Hobbit in the four-year prelude to entering production, it's clear Peter Jackson is really enjoying the shoot for his ever-expanding take on JRR Tolkien's fantasy novel. The latest video blog for the project once again fizzes with infectious enthusiasm and a sense that everyone involved felt part of an enormous family of actors, technicians and creatives based in Wellington, New Zealand. Much of this material was first shown at the recent Comic Con event in San Diego, but has now arrived online. Among the highlights are our first look at the town of Dale (which appears to have been upgraded to a city) and glimpses of Beorn's wooden lair, Goblin Town under the Misty Mountains, and even the home of wizard Radagast the Brown (a spoon-mad Sylvester McCoy.)

One cannot blame Jackson for revelling in his return to familiar Tolkienesque territory after the relative disappointments of King Kong and The Lovely Bones, and those of us who have been longing for decades to see The Hobbit rendered properly on the big screen will find it hard not to get caught up in all the matey positivity. If there was ever a smattering of information custom-designed to bring us back down to Middle Earth, however, it's the news this week that the Kiwi film-maker is moving forward with his plan to shoot a third movie set in Tolkien's universe once The Hobbit: An Unexpected Journey and The Hobbit: There and Back Again have been completed.

Some might have been blissfully unaware until reading this that the slim, 350-page fable they remember fondly from childhood is being rendered into two epic movies. The rest of us had just about got round to the idea of the book being split down the middle when an unwelcome third character reared its ugly head. According to a source quoted by the Hollywood Reporter, the move is driven by "the film-makers' desire to tell more of the story" and is now in the hands of studio bean counters, who are working to shore up rights issues and negotiate extra shooting time for a range of cast members. Studio Warner Bros is said to be keen on the idea of a third movie if the logistics can be reasonably negotiated, as well they might be given that Jackson's previous trilogy pulled in almost $3bn at the global box office.

Jackson first raised the prospect of a third film during a press conference at Comic Con. At this stage, it seems likely that the first two Hobbit movies will remain in their present forms, with the third making extensive use of appendices in The Lord of the Rings referring to events in the earlier tome and the 80-year period between the two novels.

"We have an incredible source material with the appendices," Jackson said. "The Hobbit is obviously a novel, but we also have the rights to use this 125 pages of additional notes, where Tolkien expanded the world of The Hobbit published at the end of Return of the King.

"[Hobbit producer] Fran Walsh and I have been talking to the studio about other things we haven't been able to shoot, and seeing if we could persuade them to do a few more weeks of shooting – probably more than a few weeks, actually, next year – and what form that would actually end up taking. The discussions are pretty early. So there isn't really anything to report, but there's other parts of the story that we'd like to tell that we haven't been able to tell yet."

Those who have been following The Hobbit's gestation since the beginning may recall that (way back in the Guillermo del Toro days) there was talk of one film based on the novel itself, and one "bridging" film leading up to the events of The Lord of the Rings. Jackson later ditched these proposals in favour of a pair of movies based entirely on The Hobbit, so it may be that the third film includes some of the material originally planned for the excised connecting movie. That could mean more screen time for Gandalf's meeting with the White Council, mentioned in The Hobbit but not depicted, and even a recreation of Aragorn's early struggles, or his long hunt for the creature Gollum (though these would presumably require a high-profile return for Viggo Mortensen).

Less likely, but not inconceivable, is that Jackson plans to move into pastures new, or at least tinker with Tolkien to an alarming extent. The British writer's novels have always appeared inured from the modern trend towards adaptation and expansion of popular fantasy universes. Robert E Howard's Conan has been drawn by a range of authors and film-makers, while the fabulous current TV incarnation of George RR Martin's A Song of Fire and Ice novels departs significantly from the original literary works. Correct me if I'm wrong, but I don't believe the same can be said for Middle Earth. The only stories set there, thanks largely to the close attention of the Tolkien estate, are those by or closely adapted from Tolkien. Might Jackson, as the Oscar-winning creator of the hugely successful Lord of the Rings trilogy, feel he has attained enough ownership of its universe to be able to shift and warp it into new territory? We already know that he's shoehorned the likes of Legolas and Saruman into The Hobbit, while adding at least one entirely new character that did not appear in the book. A third film is at the very least going to require a considerable amount of artistic licence: a lot of those appendices are pretty dry.