First thing coming to my mind about the Gnome is resource consuming desktop environment with fancy features and loads of bloat. Fitting Gnome to a embedded Linux device - impossible? Maybe not.
The Gimp Tool Kit (GTK+) has proven it's suitability for embedded devices, also some other parts from Gnome, such as GnomeVFS, GConf, etc. But how about the whole desktop environment? First of all some storage space is needed. At least storage space from 128 MB to 256 MB is required. Then some main memory, let's say 128 MB at least. And last quite powerful CPU, high speed ARM processor could be enough for normal operation, but more powerful x86 processor would be good bet but then we got some power and battery issues. If no problems with the power, choose x86 architechture, otherwise ARM is a better (but slower) bet.
Building up the Linux system and libraries, setting up X server, window manager and finally Gnome desktop. Gnome is quite scalable, it can fit different sized screens but too small is too small. If you're luck enough you'll get Gnome up and running with proper speed and load times. If not, you need optimizations. Everything futile must be removed. And trust me there's lot of things to remove. Starting from applications in the panel, background images, fancy window decorations, etc. and continuing to different components and packages. Test how slight configuration you can get. Then add features back if they're needed.
Now we have only one question left. Why? Gnome is quite usable desktop environment and nice on a desktop computer but how about embedded devices? First of all it's an easy start. You don't have to fight to get usable GUI to the device, no need to reinventing the wheel by implementing your own desktop enviroment. Of course there's other desktops available as well, but Gnome is well known and there's lots of applications for it. You could list a lot of benefits. But there disadvantages as well - Gnome is not designed for embedded use, it uses quite much resources and it's designed to be used with a mouse and a keyboard.
I would not recommend to use Gnome as is. It's possible to use some parts of Gnome in embedded devices or you could use some other GTK+ based desktop system such as XFce. If you still want to use Gnome or want to have quickly an desktop for the device, it's possible to utilize Gnome. It requires some time, resources and care, but can provide some benefits quicker than using a customized solution.