The Lenovo ThinkPad x230 is available with a good quality IPS display (though still widescreen and low-resolution). I own an x220 with the same IPS display, and I'm very happy with it.
I just recently got an x230 with the IPS option. The display is great and really comparable to my 11'' Air except for the coating. Overall, I love the machine. It lacks the size advantage of the Air (they are generally similar, but the x230 is several times thicker) but I was able to swap out the drive with a 256 SSD and upgrade the RAM to 16 GB which has left me with a machine that is way more capable than I anticipated. I also am really surprised by how much I like the keyboard.
That said, the ultrabook market is still in a weird state. I looked at all of the major vendors and no one really had the ideal combination of components yet. Once you can get the x230 with higher res display and a multi-core CPU, it'll be an ideal machine.
The only ultrabooks I can find with high res screen at the moment are either made by Asus or Sony. I've heard good things about the Asus UX31/32, full HD IPS displays (1920x1080) in a 13.3 inch laptop. A 12 inch laptop with 1600x900 would probably be ideal for me.
Yeah, it's the 1366x768, same as the Air. I saw better options from a few different vendors but it always came at the price of low end components elsewhere.
So you think one can like the new keyboard, right? I heard many long-time ThinkPad users were dissatisfied with the new keyboard. I'm on older X series and really contemplating whether I should get X220 or X230 in the future. Apart from the keybord type, why the hell do they dissolve the six-key Ins/Del/Home/End/PgUp/PgDn block ?!
If you don't use WWAN on your x230 (or even have the card), you can put an mSATA SSD into the M-PCIE socket. Then you can have an ssd for your OS, and a hard drive for mass storage.
I'm not sure how many developers are using 11" MBAs. 13" yes, but the 11" one is small and low-res enough that it's awkward for development (particularly development involving an IDE).
I have my X61t, with 1400x1050 res 12" display, hooked up to my HP IPS 24" 1920x1200 res display. It's a good combo for portable (yet usable res for real work) and then even better when it's docked at home.