You're in for a long wait then. Jobs said laptops with touch screens is total bullshit when talking at the new air launch.
Coding apart, it works great for these things if you use the bluetooth keyboard.
The Air is great but the real problem is when you are moving around. The iPad is perfectly natural to carry with you and to be used standing up - the Air, because of its laptop form factor just isn't.
(and yes, I run Ubuntu on it instead of OS X)
The same can't be said for other designers of 11" laptops as yet. You really need a great trackpad to work with, because you do have to zoom in at times, and a great quality screen as well. The SSD helps tons as well. The MBA is the best designed 11" I've come across.
That said, I too would love to be able to work on a tablet. Basically all I need is vim and Chrome. What I'm thinking is connecting the iPad to a bigger screen and using the pad as a keyboard, but nah it doesn't seem realistic.
As the owner of a mid-2010 Macbook Pro and a first-gen iPad, I think the new Macbook Air, which is a significant step in that direction, could replace both devices for me.
The iPad cannot be used for productivity work (coding, writing, even longer emails), but my 15" MBP is relatively clunky, especially for the type of consumption activities that the iPad excels at (i.e. reading on the couch, watching a TV episode, etc.) I wish I could have the best of both worlds.
The new iPad version of Garage Band really captures this: in some ways it's better than the Logic Pro I have on my laptop; I can play keys on it, I can trigger drums with my fingers, etc., but it's painfully underpowered (in terms of CPU, memory, I/O, etc.) to comfortably record a serious track on it (despite what Gorillaz accomplished).
I'm waiting for a Macbook Air with a full touch screen, and a new OS that fully combines the simplicity and interactivity of iOS with the power and breadth of OSX.