One quibble:
"It takes time to glean an employee's pithy attributes: work ethic, intelligence, attention to detail, enthusiasm, even personal hygiene."
You should be able to judge at least initial enthusiasm in your interviewing process or you're not doing a good job of selling your company or it's an impossible sales proposition. Either of which you should do something about at a high priority.
But I'll admit that sustained enthusiasm is what really counts and of course only time will tell WRT to that. And I'm not sure what you'd do with people who take some time to warm up to a situation (ADDED: well, make sure they've been enthusiastic about at least one prior job; if they're too young to have any/many and are already cynical you'd probably best pass on them :-).
For programmers you should be able to get a reading of intelligence and attention to detail in the interview as long as you do minimal testing (perhaps Fizzbuzz, my preferred 3 tests of reverse a linked list (pointers), recursive factorial and find error in this block of code, etc.).
Having them work out loud with you a relevant design problem is also good, although recognize that only 1/5 of programmers "get" abstraction (according to the Antipatterns book and my personal experience); if you need/can afford having programmers who don't get it, you'll want to gauge their ability to follow orders and "do it this way" "just because" the architect says so.
(There are potentially lots of slots in an organization including a startup for all sorts of competent people, e.g. look at the 2nd Coders at Work interview Brad Fitzpatrick, the Live Journal Founder. They had an older employee who produced awful code, but they loved him since his forte was quickly figuring out difficult integration problems which no one else liked to do or was good at. He handed them messy solutions filled with duct tape and bailing wire and they mined the interfaces from them and made clean versions that fit with their system.)
Anyway, my advice is to pay close attention to what this author says, just don't let it cause you to significantly relax your hiring system since hiring, working with and then firing duds is always debilitating for all concerned.