Yes, there is. The goal of Sony is to bring us the most important focal length lenses with high quality AND a good price. Look at the 50mm f/1.8 for example. Building such a lens as a pancake would either give you a much higher price or a much worse quality. I think most of NEX-shooters will enjoy Sony's choice of releasing bigger but cheaper & better lenses (or at least they [the customers] would if they would know what's the alternative). And Sony already told us they're going to release more pancakes in the future and that they're aware of the lack of pancakes. But give them time - to give us the high-quality cheap lenses first is right in my opinion.
Also, Samsung has "just" 3 pancakes. Two of them with just "okay" quality for a not so cheap price, the last one is a very useful, good quality 30mm f/2 - but for a asking price of 599€. I bet it would cost about half the price if it was kit-lens-size. Look at Samsung's lenses yourself to get an impression of their line-up:
I see no evidence that they can't, in fact, they have already produced one. They haven't prioritized it yet though. For instance, a high quality zoom is on the lensmap. This is yet to be available for the m43 system, even though it has had three years to make it. Different company, different prioritizes, and you can disagree with them, but it will take time to flesh out the system. Likely to be no more pancakes this year or the next.
Sony's flange back distance is 7.5mm shorter than Samsung's. That means that if you added 7.5mm of tubing to any of Samsung's pancakes, they would optically suit the Sony. Put simply, the registration distance difference lets Sony make bodies which are a little thinner and able to adapt lenses from many other mounts, but the lenses need to be a little thicker.
Still, the Samsung pancakes show that sone could make the lenses pretty small if they were so inclined. Sony's got a history of making big lenses, and so does Zeiss. For example, the Sony F707 had a far bigger lens than any other camera of its class. The Zeiss ZM lenses tend to be larger than their Leica counterparts, and the Zeiss ZF lenses tend to be bigger than their Nikon counterparts.
What I would love is something like the Pentax LTD 40mm 2.8. Not super fast but super sharp, super small, and reasonably priced (>$300). Sure with the registration distance the lens itself would be a little thicker.
Given that the whole idea of the NEX was to provide quality with portability, it sure would make sense to make the lenses as small as possible. The upcoming Zeiss 24mm is already bigger than the kit zoom and priced at $900. Sony might as well make it smaller and charge another $200-300 as it would fall in line with the price of the A-mount version of the Zeiss 24mm.
I would have preferred a 28mm or 35mm equivalent pancake if it is to be Sony's only pancake, that is more my complain than anything (understanding that focal length is a personal preference.)
But I think they are hesitant to do another wide angle prime, for example. And now the new Zeiss 24mm is coming out, so that covers the wide/normal focal length. I guess they just don't put a high priority on the pancake form factor itself, as much as other design factors (focal length, price point, etc.)
I see your point but I don't agree. I think a fast-ish 30mm to 35mm pancakde prime would be ideal. The 30mm macro doesn't really cut it. Personally I would have preferred a 60mm macro/portrait and a 30mm pancake prime. If they'd done that Sony would get a lot more of my money.
Personally, I am completely with you- a fast 30mm would be absolutely ideal. If they just copied the Samsung 30mm f/2 (including the price of $299 USD), that lens would not leave my camera. The Micro 4/3 equivalent is the Panasonic 20mm f/1.7, I would love that too on NEX.
The problem is that Sony seems to have designed a bunch of lenses around that spec. A fast, walkabout pancake seems like an obvious choice, doesn't it?