I have a series of short (90 seconds or so) little segments in a sequence that are very similar to each other that I've just created one after another in the timeline. There are about 50 of these. They are each made up of still frames (a .PSD Photoshop graphic), overlayed text (Premiere text) and audio - no video. As I create each little segment, I'm exporting them to a Quicktime movie (H.264, 50% compression) and the Range set to Work Area Bar to control what gets exported. Although the resulting Quicktime movies play just fine, the problem is that as I get further and further down the timeline creating these movies the resulting Quicktime movie files get larger and larger. The first movie is around 12MB, the second around 16MB, the third around 21MB, and so on until the 50th one is over 400MB. Again, the movies play just fine, but there's no reason I can see that the 50th one is so gigantic (over 400MB in size) compared to the first one (at around 12MB).
This is a Windows XP Pro machine with 4GB RAM using Premiere Pro CS3 3.2.0.