Well, after googling a while I've seen at least two other "/40" models, one of them were in Dutch site
. I guess these kind of badges was used in latter versions of HD-models and therefore they are more rare than a600 or even a600hd badges.
Afterall, I'm starting to restore this baby. As you can see from the picture, it's running smoothly from a 4 gb cf from ebay... Anyone with a spare 40 mb hd and willing to sell it? ;-)