I think this kind of process for interviews is really prevalent in the US, especially for big companies.
And when I read here and there how easy it is to get fired there, I don't understand why you put such a barrier for the entry!
As a programmer, I'd feel insulted if I had to pass through 5 layers of requests and experiments until seeing someone face to face. I'd let go after the 2nd or third.
If a company is making his future employees pass through hell just to have a chance of going in, thanks but no thanks. That's not the company I want to work for.
My 2 last job interviews (for 2 small companies in France) went in 2 shots: one on the phone, then face to face, where I was faced with 1 or 2 "programming" questions, then ~1 hour of discussions about what the job was, what I did before, and how comfortable I was feeling doing this job.
Now, these were (are) small companies, where there was no HR that was PAID to design lengthy interview processes. I directly talked to the guys I'd be working with, and I don't think they made a mistake taking me. I'm still working in the 2nd one, as an happy programmer.
There's a question of trust in an employer/employee relation. I had a 3 month trial after both my interviews, and I was absolutely ok with that. This period is made for that: if I didn't fit, it would show in the first 3 months and I'd be thanked. No need for a 2 month recruiting process!