welll the fixation on drive letters is simple... Users are simple (nicer than calling them Dumb)... Once they finally understand to look into "my Computer for their stuff, you can't expect them to learn something else"Then again, there are some apps that must have a drive letter to access their stuff, UNC will throw them. They are probably very old and no longer supported by the writers.
What ever the problem is, 26 is really all that anyone SHOULD need, most likely the problem is an inefficient structure where a thousand little things are shared and mapped to their own letter...
This is a Network Administrator's problem, where SOMEONE needs to move/maintain their network and design things efficiently. DFS is a partial solution, and an easy way to keep the users connected to their resources, while things are being moved around...