The "iPad is a consumption only device" meme needs to die. It's completely, totatally wrong.
That lack of featurism causes app developers to reinvent lots of basic stuff in their apps to get all the features they want. And sure, that happens on PCs too - but to a far lesser extent.
If you're familiar with the unix philosophy of making apps as filters, making them do one thing, and do it well - you'll understand how productive it can make you - and how there's no chance of reproducing that on a (non jailbroken) iPad.
And yes, I wasn't referring to art, but the software itself. Try creating an iPad app purely on the iPad - I wish you luck.
On the other hand , describing the iPad as a good computer for application development because you can SSH to a remote server and run VIM seems a little stretched, by that standard the Nokia that I had in 2002 was a dev machine.
There's a reason that Apple continues to support and develop OSX.