Oh man, recording gameplay was a nightmare. I tried so many different solutions before I found one that provided high quality and fast frame rate capture. Hopefully others can find this post useful and save some time.
1) I was surprised to find out there wasn't an app you could download from the App Store to record your screen. Apparently there was one a while back called DisplayRecorder, but Apple took it down since it used private APIs (not sure why Apple is so against screen recording). It's easy enough to find the .ipa online, but I didn't want to jailbreak my device so I could install it just for one app.
2) Then I tried Reflector to mirror my iPad4 to my ancient '08 MacBook Pro, but I experienced lots of frame skipping and the camera scrolling was not smooth since it only records at 24 frames per second (I think? Could have just been my laptop couldn't keep up). (It also costs $13). I also tried AirServer briefly (another AirPlay mirroring app with a free 7 day full trial) but same problem there.
3) I did a bit of research and came across gameplay-sharing services with libraries you could integrate for free (like kamcord) but the barrier for entry was too much for me and I didn't plan on allowing users to share gameplay videos anyway (it is a pretty neat idea though I must admit). I also found some guys online who rolled their own video recording code, but why reinvent the wheel.
4) I finally came across this fantastic git repo, https://github.com/coolstar/RecordMyScreen which is essentially the source code for the original DisplayRecorder app, and I ended up manually compiling the source in XCode and deploying to my iPad (this requires the $99 Apple developer license of course, but most people on these forums have that). I tweaked the source to capture video at 30fps instead of the default 24 and I was happy with the results. (I had tried setting it to 60fps initially, but then I noticed a few hitches, so while not ideal, 30 got the job done).
As for audio, unfortunately the APIs the RecordMyScreen project uses only record audio from the microphone, so for this I cranked up the audio on my iPad and played the game in a nice quiet room being as silent as I could, haha. (I also applied a noise removal filter in Audacity after the fact). I could very well have plugged an audio cable from my iPad into my microphone port and recorded high quality audio, but I was being lazy.
One caveat of RecordMyScreen is that it doesn't support full 2048x1536 resolution. It only supports half for iPad retina, so 1024x768 (which is still 720p so I'm happy with that).
The reason I cared so much about the frame rate was because I worked hard to support a (nearly) consistent 60fps for Star Thief on low end machines, ala iPad1 and iPod Touch4. The difference between 30fps and 60fps with constant-scrolling games makes a huge difference. Even when taking delta frame time into account in my camera movement code, it was a night and day difference between the two. (Curious to hear if others have seen similar results?)
One last note about audio for those of you who have read this far -- I ran into syncing issues (aka: audio drifting) when recording video at non-24 fps. I'm not an editing guru, so the problem could have been something as trivial as a GUI setting with how I was importing my audio files into FinalCutPro, but I had to "slow down" my audio by just 1% and it magically synced perfectly. This was literally like 3 mouse clicks away in FCP, but I swear this took me FAR LONGER to figure out than it should have.
Whew that got long! Sorry for the wall of text!