In official Blender 2.71, by spliting a strip with a sequence of 722 images with Separate images function bpy.ops.sequencer.images_separate(length=x)
the .blend file jumps from 600 Kb to something near 132 Mb, without any packed file.
It seems a bit exagerated compared to the same steps done in 2.70a, where it increases from 570 kb to 4.4 Mb, much more reasonable.
Scientific Linux (CentOS like)
Linux lajeado 2.6.32-431.20.3.el6.x86_64 #1 SMP Thu Jun 19 14:01:59 CDT 2014 x86_64 x86_64 x86_64 GNU/Linux
Graphics card: 0f:00.0 VGA compatible controller: NVIDIA Corporation GT200GL [Quadro FX 3800] (rev a1)
Broken: 2.71 hash: 9337574
Short description of error
Exact steps for others to reproduce the error
Based on a (as simple as possible) attached .blend file with minimum amount of steps