Interesting point mark. This is especially so with laptops, such as my own, which has a fifteen point some inch screen, with a mere 1280 x 800 resolution (widescreen). Ideally, the resources should fit on a 1024 x 768 resolution, since that is the standard 'small' resolution these days, and almost every computer, except some wee little netbooks that are good for nothing support it. It (I believe), is the default resolution in Glest. Larger monitors CAN view smaller resolutions, but smaller monitors cannot view larger resolutions. The point is, if it can't fit on a 1024 resolution, its pointless. I'm not sure how many resources that is (6?) but that's an effective limit.
Multiple rows might be a good idea, however, in the mean time, it does make an effective resource cap... [Insert the evil emoticon that doesn't exist here]
Turning back to the topic of many resources, you'll notice games like civilization IV have many types of resources. However, only a handful (ie: oil, uranium, iron, bronze, aluminum) are actually needed for unit production. The many others simply increase food, health, and happiness. In short, it only uses a small amount of resources. However, on the other hand, it has very large maps that are generally the size of the world, not a small patch of land (you can have a planet that looks like earth and has resources like earth). It also doesn't use the resources in the same way, needing only one resource to build anything that is needed (ie: you only need to discover one patch of iron to produce as many iron-using units as you want).
I don't see glest benifiting from too many resources...