Several thoughts, to build a round escape pod, have you considered a small weather balloon to give you the size, like the ones that have been used by people to send their cell phones and cameras up to the atmosphere limit. Inflate one to the proper size then resin it to build your "Ball", then mold it to make a negative mold, then glass fiber and resin to build it.
Similar to :
http://bellwetherreports.wordpress.com/2011/10/03/take-shelter-in-a-floating-tsunami-pod/
http://newcosmopower.com/
http://inhabitat.com/prefab-friday-remote-igloo-shelter/ is a section dome that give you the idea of making your own mold and section together a pod.
For the elongated escape pod, possibly expanding. I did some stuff with plastic 55 gallon barrels many years ago, where we fit a 30 gallon inside a 55 gallon barrel for a biodigester. I think you could modify that style to make an expanding escape pod. Maybe slice a barrel lengthwise and add in a strip to enlarge it, with the expanding portion possibly being another 55 gallon of 30 gallon barrel. Go to :
https://energypedia.info/index.php/Types_of_Biogas_Digesters_and_Plants#Gas-Holder it should take you down to the floating drum, which is similar to what we built, to give you the idea. If you split 1 barrel and put in a section to increase the diameter, you could have the second barrel slide in and out to "expand" the pod.
And I seem to recall a diagram where there were 5 escape pods in the I think the port docking ring, they needed to be pulled out, loaded then ejected. They were 1 person pods and were stored collapsed 2 on each side of the corridor and the fifth under the floor board. I cannot remember where I saw it that diagram though, I think it was the turbolaser commentaries (I THINK) not sure. But expanded they were 2 meters tall and 1.5 meters across. That is all I can remember about that.