I really think the ThunderBolt display will be updated in December. They've announced the MacPro, (first sometime in 2013, then fall, now as of today, December. I think they will will have a whole desktop event then, with the MacPro, MacMini, non-retina MBP & TBD 2.0. They have specifically said at the MacPro announcement that the MacPro will work with 3rd party 4k displays, so I highly doubt this to be a 4k display. The other option would be to dump this product altogether, but I think with the iMac design already done, they will want to show off the new mini and pro with a new, finally-updated, monitor/hub. While the numbers of these produced may be small, I've got to think that at the current pricing, it's a profitable product not worth walking away from, especially considering the physical design is already finished. With the Pro coming in at prosumer pricing ($3K), there's a lot of Apple customers who will want the prestige of owning the flagship, made in the USA computer. Most of those people are not going to turn around and buy a 4k display for $4K, or buy a cheap dell, but will want to show off their Apple status symbol with a new ATD. Considering that sales and supply of ATDs has been low recently due to a very outdated design and ports, and that they no longer can sell them in Europe due to new EU standards and lack of a internal fan shroud; I can not understand why they wouldn't update this product just in time for Christmas. With MagSafe 2 and USB 3 standards for so long, plus now TB 2 as a Pro standard, they would do well with an update that is compatible with every single current Mac they sell. People here were saying they would never come out with a new Pro for years, and yet they will; I believe the same is true with this product. Fear not, Apple still wants your money.
Specifications:
Current 27" iMac physical structure, available with stand or VESA mount, just like current iMac.
Current iMac low glare screen
Current iMac speakers
MagSafe 2
Current iMac I/O with possible addition of ThunderBolt 2.0 ports
Current imac IO ports include:
SDXC Card Slot
Four USB 3.O
Two ThunderBolt 2.0 ports (possibly three total including tethered cable, or they might want some extra for the cable this time)
Headphone
Gigabit Ethernet
Full Res FaceTime Camera/Microphone
I think the above is a given, but Apple might have some other additions:
HDMI 1.4
Greater than 2560-by-1440 resolution, but not 4k
Graphics Card, or a better yet, an upgradeable slot for it, (TB2 is fast enough to utilize this in a hub device)
AppleTV built in, potentially the iTV devise Jobs was talking about for the last couple years of his life.
Optional Remote, Free IOS remote app for your iPhone/IPad
$999 + potential upgrades
So the rMBP you were waiting for came out yesterday, either wait for the next gen ATD, or get them both now and trade out the monitor in Early December when the ATD 2 is out. So yes, for it's features the ATD is overpriced, unless you find it used or refurbed for $700 or less; but the new ATD 2 will be a good looking bargain at $999 for a much nicer renovated display/hub. Good Luck.