This thread is really old. There are more recent threads on the topic.
You can look into Electrum or Armory as a way to aid your offline transaction needs.
I may be old fashioned, but depending on Electrum or Armory (Armory now offline), which in turn have a bunch of other dependencies, is not a solution to such a simple problem. Problem being a way to prepare a transaction and then sign offline.
I understand the point about hardware wallets, but in my case I prefer to use an offline Raspberry Pi machine. I am looking for a lightweight solution to signing offline, such as this, but there's nothing I can find. This should be an easier problem.