Yes I was talking about color depth setting. Wasn't sure what Windows you had and if others than XP have other settings besides 16 and 32bit. Reason for this is that I have my laptop which I use both in work and home, in office I have second monitor (well today got my home monitor back too) and for that reason my computer has used 1 or 2 monitors depending where I am.
In both configurations my screen 1 which is always laptops LCD can run 1400x1050 but in 2 screen configuration it can only show 16bit color.
And when I play Combat Mission which used 24bit color, and haven't rememberecd to select 1 monitor configuration, game selects smaller resolution than 1400x1050 I want it to use.
I think people shouldn't use resolution to change size of items in screen. For GalCiv resolution doesn't matter because it anyway takes your full screen (in 800x600 mode possibly scaling graphics and running LCD in non-ideal resolution resulting poorer quality). And in normal usage you can resize any Windows font/icon from preferences.
I think your only option to get it look bigger is to have bigger monitor size, 17" or bigger. So I think you need to use external monitor, if your old CRT screen doesn't fit on the table get bigger table or bigger external LCD monitor.
Or other option is to try to see if you can play game without minimap which is too small for you. Have you tried F9, it shows same map as minimap but you can't change display options in it.
But hopefully you get your game running and find out good solution how to play it
~SDC~