Adding a new type for customization.

[Vailry]

How does one go about adding a new customization type? Currently there are text and file. Text is limtied to 250 characters.

I now would like to add Text_Something and Text_Something2 each with different character limits, for different product types and usecases.

I've looked into Customization.php but both search queries, "file" and "text" didn't quite give me any result that looked like it was the right thing to copy, paste and rename.