Beyond hilarious
While I completely understand the OP's request for such a solution, the notion of needing an remote for a device that is often a remote is hilarious to me for reasons I cannot currently fathom.
You could probably control your iPad from your iPhone, but I'm betting Apple very much intends for the iPad to be used within a foot of our faces, so a solution would be limited.
Back in my day, we hooked our ENTIRE laptops up to TVs, mirrored screens, and watched ****** rips we DOWNLOADED, not streamed, from creepy Limewire-type sites you're damn right we walked across the room to change the video.
Of course, back then the biggest innovation in cell phones was t9, which didn't do much as a remote.
Kids today, sheesh.