Touchscreens certainly have their advantages. Not only do they offer an infinite amount of flexibility input-wise, they can even be switched to display output graphics as needed. In some situations, though, it’s hard to beat physical buttons. For an input that you need to always be in the same place, with the physical feedback of feeling it engage, they work quite well.
You could make something out of an array of buttons, but for a ready-made solution with a distinct look, why not check out these numerical inputs from Zachtek?
Slim Clicky Keys
This first keypad option features keys that sit fairly low, and allow you to print your own characters or symbols using a printer or pen. It acts as an Arduino shield, communicating via I²C or serial.
Long Stroke Clicky Keys
For another customizable solution, this keypad functions in the same way as the first, except for its long stroke and non-clicky operation. It seems that both would have their uses, and just depends on what kind of look you’re going for. It would seem that the long stoke keys would be especially well-suited for a custom keyboard shortcut application, and an exotic retro-futuristic robot control panel would also be quite entertaining for either!