1/48 scale won't be small on a Gundam. I just built a 1/144 Gelgoog Marine and it is about 6 inches tall, so if it was 1/48 scale it would be: 18 inches tall.
For me the build will depend upon how much time I have, and what the categories are. If I have a lot of time, it will be a diorama, not a lot, something else. Sorry keeping my ideas a secret on this one.