Anyone built a raised bed/planter/trough within a sunroom? If so,...

What are the issues?
What atre the solutions?

Our home has a add-on sun room. We'd like to create a flower zone approx. 8' along one "interior" wall (the house' original stucco exterior). We're thinking we'd do so by building a raised flower bed/planter/trough out of 1x12 wood boards.

The issues that I think we'll have are:
a) moisture proximity to the wall. But, how does the wall's barrier (sheeting under the stucco) impact/mitigate this issue? Would an inch gap between the planter and the wall be sufficient?
b) insect/critter/termite bridging. Again, how do gaps, etc. help or even preclude? and... What's available (product or materials) in a non-wood material that is big enough and surdy enough if the wood itself is an insurmountable problem?
c) planter drainage -vs- deck moisture/leaks from the planter. How have others built/how should we build a pan for this case?

found this on diy, and wonder if it can be modified for inside...

http://www.diynetwork.com/diy/ic_planters_pots_boxes/ar...3967_2874638,00.html

wow! thanks!