Great list, it can be easily implemented, though what I've read is that there is a certain limit to how much data can be grabbed or else OPL becomes unstable. But I can test it on my own free time to see how it behaves.
Potential for Display:
Analog, Digital, Ana/Digi /multi-icon
Memory Card/Save Size
Number of Disks
Pressure Sensitivity - Jak3...
Progressive Scan/other Scans /multi-icon
Multi-Tap - Guy Game...
Online/Network Adapter/Additional Players through Network /multi-icon
Very good ideas. It gives me a good starting point. I might work with you on this by sending you a special test theme that supports all these extra icons and once we both can confirm it looks well and also OPL doesn't croak, we might later see an update to my themes. :)
I would guess that for things like Analog/Digital, there would be a 3 icon set showing half the D-pad and Stick, and only the ones that the game uses are lit, 1 Digi/2 Ana/3 Both. Vibration would be a small controller with the (( motion )) marks around it, grey for default/no vibration. Number of disks could be as simple as stacking the Disk Image under the CD/DVD Disk logo, One disk is normal/defaut, 2 would show part of a second disk under the first, almost pancake like... Multi-tap could just be an + added to the Number of Players, or an additional icon next to it that has a + on the number of additional players that could be added. Something simular could be done for the Online/Net Adapter/Add Player w/ Net... Games that use the Headset could have a little Headset.