Display file/folder/drive names in full on the desktop

You can't do this in the current Finder. You should look for an alternative that makes your desktop behave more like Windows. (It sounds like a Windows feature to me.)

Open Terminal and execute:

$ defaults write com.apple.finder FXDesktopLayoutGridCharCount -int 50

Then you will have to restart finder:

$ killall -HUP Finder

This will set the maximum characters to 50, you may change it to the value that fits you the best.

I don't think you can do this without hacking the Finder.

OS X can handle really long filenames, but it also cares about looking nice, mostly because other operating systems have a strong potential to look ugly, and Apple's developers care about design aesthetic.

As a result, icon displays are limited in the amount of text they can display to two lines and whatever horizontal space is available in the grid.

The Finder DOES still have the capability to display gratuitously long filenames in full (or nearly—the limit seems to be about 1000px): just open the Desktop in a finder window, change your view to list, and adjust the window size and column widths to taste.

You can go to View -> Show View Options (⌘+J) and set the grid size to max, although really long filenames (with no spaces) maybe still have ellipses.