Upon further research, googling the 'Lg Philips 10.1" wsvga' part listed by Dell on my invoice, I discovered that the Mini 10v uses Philips part number LP101WS1. Then, googling that part, lead me to conclude that indeed, Philips has several revisions of that part:
LP101WS1 (T1)(A1): 1024x576
LP101WS1 (T1)(B1): 1024x600
There also are B2 and B3 versions for sale here & there, they are also 600.
We don't know when Dell's factory switched from Philips' A rev to B rev, but it looks like the units being shipped and refurbished recently are of the B variety, at least in the US.
My Mini 10v arrived today from the Dell Outlet ($229 bought last week), and it has a 600 display. Whew, I was hoping for that.