Joel Spolsky has an excellent article on office design, especially manufactured walls. It's really insightful.
Joel takes you through how FogCreek, paid for expensive office renovation, with their first office. All of which wasn't really tax deductible.
But with their new office they are going to use manufactured walls. Since manufactured walls are a real asset, not only can they write off the office expense, they even get to lease the purchase.
This explains why so many tech companies prefer cubicle farms over having real walls. But I think Joel's right, with manufactured walls you get the best of both worlds.
We're starting to outgrow our current office at Taylor Data Systems. I'm glad there are other options for us besides cube farms.