I've noticed that Parente talks about the models as 1/48 at his Dust page, but so far I hadn't really looked that closely at my own Dust minis to really think about the scale. I had of course noticed that they were thinner and taller than, say, my Imperial Guard troopers...
So I brought out some unpainted 1/48 Preiser figures and compared them with my Dust and GW Imperial Guard minis, and tried to find figures that were standing fairly straight. The Dust minis are markedly taller than the GW minis, but still slightly shorter than the Preiser figures. I'd say they are about 2 mm shorter, even though I've taken the fact that the Dust figures are crouching more into consideration. The only Dust woman, Sigrid von Thaler, is spot on for the femaie Preiser figures, being about as tall as the Dust men.
Looking at body thickness the Dust figures compare quite favourably with the Preiser figures.
Dust is definitely closer to 1/48 than the regular wargaming scales, although not absolutely perfect. Some time ago I bought a Tamiya KV-2 to use as the basis for a W40K Grot tank, but I think I'll just build it as a KV-2 and nothing else, repainting my Red Blok minis at the same time. I'm definitely going to take a renewed look at the rest of the Tamiya line now!