1. Scroll through all your home screens and folders to see if an app with a brown icon named Cydia is installed
2. Check your settings, is there an additional set of settings there that isn't usually? (I'm not jailbroken at the moment so help me out with that those are guys)
3. Check the configuration of the router, is any port forwarding setup? Are there any unknown computers listed in any of the logs?
4. what version of iOS are you using? if 4.3.5 it is extremely unlikely you were hacked.
5. On your home network open up a Terminal on your Mac when your iPad is connected to the Wifi, check what IP address your iPad is assigned and then type in terminal:
ssh
root@xxx.xxx.xx.x
(replace the X's with your iPad's IP address)
If that prompts you for a password or says something about an unrtrusted key instead of just timing out then you have SSH running on a default port and are somehow jailbroken. If it times out it means you are either not jailbroken or the hacker was smart enough to install SSH on a non standard port.
WEP is easy to crack so it is quite plausible that someone joined your network and sniffed out your Amazon session BUT even then it would be using https, which would prevent a straight forward hack so they couldn't just hijack your session. A man in the middle attack is possible with https but is quite a sophisticated hack.
I read through a lot in this thread so I can't recall if the browser history on the iPad corresponded with the Amazon purchases?
It is just all so implausible, to accomplish what you are describing all these events would need to take place:
1. You visit a site that uses the same exploit as jailbreakme.com but uses it for malicious purposes, installing SSH and preventing the device from going to sleep
2. Someone cracks your WEP based Wifi Netork and either are just really lucky or they somehow tricked you into visiting the malicious website so they knew to target you
3. They can SSH in and install what packages they want if a VNC server wasn't already installed in Step 1
4. Connect via VNC and use your iPad remotely, they bring up Amazon and see that you are logged in with one click purchasing so go crazy but neglect to change the shipping address either through stupidity or on purpose as they knew you were away from home.
That sounds very, very, very far fetched hence all the people doubting your story on here.
Now for an extremely personal question... Have your wife and you been having any kind of issues lately? If you didn't somehow make the purchases yourself then the next plausible explanation is she did out of spite or for whatever reason.
Does anyone else know your pin code or potentially have access to the device before it was put to sleep?
It just sounds like someone with physical access has tried to scam you and it wasn't any elaborate hack, as they would have known to do something as simple as clear the browser hoistory.
Anyway gotta run...