For the smallest possible footprint you should really consider RamTEX. I have used it on two projects with 8-bit PICS. The ROM space was about 35K in my applications with ~1K for RAM (amount depends on whether you need RAM buffering for the display). ROM space depends on the graphical features you want or need.
They provide full source and the one-time price is quite good, less than $1000 (note that the prices listed on their web site have to be converted to dollars, or whatever your currency is). There are no royalties or per-product restrictions.
They provide a number of different size and style fonts and basic drawing calls (line, pixels, box, etc.). It does not have any defined "objects" such as buttons or menus, but I was able to implement a pop-up menu without too much trouble. It does support "viewports" that can be used to define text boxes, menus, etc, each with their own attributes.
It also comes with a simulator that runs on a PC so you can develop display code on your desktop before moving to an embedded system.
