I use modified Flames of War rules for my 15mm Superhero gaming sessions. I used some simple prototypes, but have recently created more detailed character sheets that track health and energy, as well as list of out actions and special rules for each character. I constructed the sheets in Excel, exported them to Photoshop for some detailing, then digitally printed them as 5x7 photos at Costco (for $.57 each). I think they turned out well and look forward to using them in future gaming sessions.
Below are the Guardians of the Galaxy: