If you can't find exactly what you are looking for, you might consider buying one of the rolls of reflective material that you can cut to size.
Some of it looks dark grey/black under normal light so it blends in nicely during the day but it does reflect well at night - like Scotchlite material.
I had a hard time finding some myself. So I went to a local auto parts store and did what Pookadog mentioned.
I got the stuff that you see on 18-wheelers. Red/white stipe (because it was inexpensive and VERY reflective) and carefully trimmed a piece of red for each side. It looks amazingly good. I actually like it better than the plastic reflectors. Not cheap-looking at all. And MAN does that stuff reflect from all angles.
Also, there are some very cool reflectors on eBay for all of $20 for the rear of the bags. They are a color match the bags in the day time and turn white when illuminated. They cover most of the rear surface of the bag and are realatively easy to install.
Good idea on the side reflectors. I don't like the OEM ones and mine were set up with the yellow ones. I guess that is the Euro color?
Yes, that is the tape I cut to fit. Shines like a beacon!
Also, the reflective stuff on the rear of the bags is black and only reflects when the light shines from your location. I like that stuff a lot.
I've got a spare set out in the garage. For a beer each plus a nominal shipping fee, I can be convinced to part with them. Feel free to send me a PM if interested and I will let you in on my beer of preference.