Ebay is a strange market for corals. Plus I see allot of hyped up stuff selling on ebay. For example $500.00 for blue polyps! I don't know how kenya tree coral ships but I do ship green nepthia from time to time and it does well (overnight). Personally, I use fedex priority exclusively. It is expensive, but I have not had any complaints when I give freebies to help cover that cost. I see people using priority mail packages all the time. If your shipping close enough, the box may make it in one day.
Materials?, I use 9x9x9 boxes, then I cut basement styrofoam from HD to make a box that fits tightly inside of the cardboard. I seal the styro with 3M weatherstrip duct tape. In the winter months, I poke sevral small pencil sized holes on the top sheet of styro to vent the heatpack. I use 60hr heatpacks on extra cold days and 40hr on more mild winter nights. You also have to keep in mind the destination, weather it be the final destination or carrier sort destinations. Your box may be going to WI but may stop as far south as Atlanta. The temp diff could get quite extreme.
If you are a hobbiest and not a business, you can post your kenya frags at the selling or trading forums right here on RC for free. You never know what kind of deal you might swing for a trade.
Keith