Yes even with that relatively short exposure time a 200mm lens unguided will trail. I'm just going by my film experience but since the area of the 300D chip is a little smaller than film the effects would seem worse.
Time wise trailing is also worse near the celestial equator. You can go for longer near the poles.
From my not so good memory max exposures for various focal lengths for 35mm film are as follows. 50mm lens 15 seconds, 135mm lens 6 seconds, 200mm lens 4 seconds, 400mm lens 2 seconds (rough figures).
For the 300D you may get even less. With my small 1/2 inch CCD I will get trailing with the 135mm lens in 2.5 seconds and the 200mm lens 1.25 seconds.
In theory if you zoomed up on a small spot of film I guess the trailing would be the same for all formats but viewing an uncropped image the larger formats don't look as bad.
You can imagine how long a "through the scope" shot would take to trail undriven. Makes one appreciate motor drives eh?
Not sure what the halos are. Was the crop from the middle of the pic or to one side?