I saw two curious entries in Instapaper’s device stats today: one iPad2,5 and one iPad2,6.

(There were also a few iPhone5,1 devices, but that’s not a surprise — that’s almost certainly next month’s new GSM iPhone.1)

These device models, as reported by the OS, could be faked by a jailbreaker with enough free time.2 But I’ve never had a device show up there that didn’t end up being a real, about-to-be-released Apple device.

iPad2,1 through iPad2,3 are the iPad 2’s original Wi-Fi, GSM, and CDMA models, respectively.

iPad2,4 is the 32nm die-shrunk update that quietly replaced the 16 GB Wi-Fi iPad 2 when the iPad 3 was released, yielding better battery life and lower cost, and probably partly responsible for the iPad 2’s price drop to $399. From AnandTech’s detailed review, this remark now seems prescient:

It’s rare these days that we actually see a pure die shrink anymore. With Intel’s tick-tock model we almost always see increases in functionality to accompany each process node shift. … With Apple’s 32nm A5 however, we truly end up with a die shrunk version of the 45nm A5 SoC. About the only part of the computing world where we see these pure shrinks is in the console space where performance doesn’t have to go up within a generation, but cost must go down.

As far as I know, this was the first time Apple invested in a die shrink mid-cycle for any of the iOS devices. They haven’t even done it for the still-sold iPhone 3GS or iPhone 4. The decision to revise the iPad 2 internals, therefore, seemed a bit odd at the time, but makes a lot more sense now.

The iPad2,5 and iPad2,6 could be boring: GSM and CDMA versions of the die-shrunk iPad 2 so the shrink isn’t only available on the Wi-Fi model, bringing lower costs to the other iPad 2 configurations that are still for sale. But now, even later in its lifecycle, that would be a pretty strange move.3

The much more likely explanation is that iPad2,5 and iPad2,6 are the new “iPad Mini” in Wi-Fi and GSM, and I haven’t recorded the likely iPad2,7 CDMA version yet.4

If so, this suggests that the iPad Mini is, effectively, an iPad 2: an A5 with 512 MB of RAM and enough GPU power to drive the Gruber Display, but not a Retina Display.

It’s a textbook Tim Cook supply-chain move: selling the last generation’s hardware at a lower price point to expand marketshare.

But this time, it’s more dramatic. Rather than just sell the original iPad 2 with a price cut, they’ve made a new product designed to be far less expensive from day one by combining old and new parts: the 32nm iPad 2’s guts, larger-cut iPhone 3GS screens, a smaller case and battery, and the new iPhone’s low-power LTE chip for $100 more.

This is all speculation, of course, but I’m convinced: like the leaked Dock connector, this move is so ingenious that it’s most likely to be what Apple has really done.

I bet they could sell that for $249, and that would be a steal. The iPad 2 is still great by today’s standards, and in some ways,5 it’s actually better than the iPad 3.

This is going to be an interesting two months.