I've been looking for a way to load sets without having to touch my computer. Sadly, you can't MIDI map file browser elements. I did find a pretty cool way to do this using Novation's Automap for iPhone and iPod Touch.
I got it configured and working on my iPhone and have been using it for a few days and it is working well for me.
In addition to the app, you need Automap Pro as it supports assigning keystrokes and multiple keystrokes to buttons. Pro also supports multiple Automap devices.
In the screen shot on the right, you can see that I assigned a key sequence to take mouse focus from a scene into the file browser to load a set. I've also mapped "n" and "enter" so I can dismiss dialogs on load. Space is mapped so I can stop live prior to the load.
Note, the on the current iPhone OS, you have to use WiFi for communications as bluetooth is not supported for apps. So, before you go to a gig, I recommend you create a secure Ad hoc network on your system then connect the iPhone to this network rather than hoping for a WiFi setup at the venue. I've got this all working on Windows 7. iPhone seemed happiest with "WEP Encryption".
I'm really liking using the iPhone as a dedicated device to send keyboard macros to live so I don't have to take my Launchpad and my Remote SL out of default modes to map these functions. Plus, the iPhone is really easy to see in the dark.