The Latitude XFR D630 is basically a Latitude D630 in full body armor built to withstand extreme temperatures, falls, moisture, dust, and more.
Dell isn't really breaking any new ground here. Panasonic has been doing its Toughbook thing for a while now, and neither is Dell trying to beat Panasonic with lower prices. At a starting price of $3,899, that's more than the lowest-priced configuration of the Panasonic Toughbook CF-30, the Latitude's closest equivalent. So why rugged and why now?
Is Dell "tough enough?" It's certainly pricey enough, but while it's a niche market, it shows Dell is spending a lot time and effort on the business notebook segment.