For comparison, Microsoft's everyday Comfort Curve keyboard only registers four simultaneous depressions. That's enough for combinations such as Control-Alt-Shift-X, and enough to keep up with a fast typist who presses a second or even third key before the first has been released.
So why 26? Despite our opening comment, it's not for the benefit of people with an unusually high number of digits.
Like other SideWinder devices, the X4 keyboard is aimed at gamers, who (presumably) are adept at pressing multiple keys with one finger or who use a keyboard in tandem.
"We're always looking for new and novel ways to enhance people's interactions with their PCs," said Steven Bathiche, research manager of the applied sciences group at Microsoft.
Other features include macros (multiple keystrokes triggered by one button), adjustable backlighting, and mode and profile switching (to suit different games and users).
Shipping next month, the SideWinder X4 will cost $US59.95.