Pose lots of unanswered questions in a PhD thesis chapter? I am just finishing my computer science PhD. It has five research chapters. The first four pose many research questions and answers all of them; they are complete in this sense.  

The fifth chapter is a bit odd. We have just launched a three-year field trial of vehicles. I was responsible for many of the field trial design parameters: Who are the participants, how do we measure and gather data, how do we transmit data, what hardware/software do we need, etc.? Most of the chapter is methodology-focused and talks about all of these design decisions and how we made them. However, I am graduating (my defense is in a few weeks), and many of the interesting research results of this trial won't be available for months/years after a significant amount of data is collected. 

So my question is, is it odd to have a chapter of the following form? “Here are a bunch of really interesting research questions, and here is how I helped design a trial to answer them, but that said, I do not present all the answers here because they are not known yet.”
The posing of "open" questions is quite common in doctoral dissertations, usually in the final "conclusions and outlook" section.

However, your situation is a bit different, in that you have an actual project that is designed to address these questions, but the study is too long for you to wait to include the results in your PhD thesis. Given this, I would basically do what you've said: introduce the basics of the case study you've designed, what it's designed to do, and so on. You just won't be able to present the actual results of the experiments. If this is clearly communicated to your committee by both you and your advisor, then this shouldn't be a major problem.