I've heard the same thing, and I spoke this week with one of the SLC application engineers at Milwaukee who has a handful of beta test units on his desk.
The urgency kind of petered out of this development when RSI delivered a Windows 2000/XP capable driver; even if it is a pain in the butt to start and stop it does work.
I think they've put in two serial transceiver chips, one for RS232 and one for RS485. That's strictly rumor; I have not seen this product, though I hope to at Automation Fair.
PC's without serial ports- that'll make a USB/PIC a lifesaver for folks who use and maintain DH-485 networks. I hope they test it with PanelView upload/download, because that seems to be the biggest bugaboo for PIC users.