The iPAQ K3 (codenamed Obsidian) repotedly would be a 2.8-inch flush touchscreen phone (but wouldn't come with a stylus). It'd sport quad-band EDGE and tri-band 3G, with roughly the same Qualcomm processor as the HTC Snap. But it goes one better on the memory side, with 512MB of ROM and 256MB of RAM (compared to the Snap's 256/192). There's WiFi, Bluetooth 2.0 and an honest-to-goodness 3.5mm headset jack.
We're still a little iffy on the age of these slides, and thus the launch date is still kind of up in the air. But Windows Mobile 6.5 is listed as the one and only operating system (and also as the browser, but we'll let that go), so we wouldn't expect it before fall, at the earliest.
But that said, this could well be the messaging monster we've been hoping for for some time now. And the inclusion of a 3.5mm headset jack is going to make the difference for a lot of people. So, welcome back, HP. Good to see ya.