Yes, you read right.

I've seen Asus and PowerCooler HD 3870x2 cards, which supposedly support no less than 4 digital outputs on one card - all DVI.

"The links?", I here you scream... Here you are:
Fudzilla - PowerColor's new HD 3870 X2 design
Boot Daily - Boot-up your tech! - ASUS Announces Radeon 3870X2 with Quad-DVI Output

Additionally, only earlier today, I saw a Palit 9600gt "Sonic" Edition with
  • A DVI port
  • Another DVI port
  • A HDMI port
  • A Display port

Here you go:
Computer hardware and software at amazing prices, available online from Scan Computers UK - Press Release :: The 3D Graphics Solution for the Future – Palit GeForce™ 9600GT Sonic Supports Four Display Outputs! : Page - 1/1
(Pictures of similar product here.)

So what's the deal?

It's reasonably easy to prove that the 3870x2 MUST be able to output to 4 monitors. (If not, no need for a dual-DVI header, there'd just be a "cooling slot" instead.) I don't know, though, about the 9600gt, which would be my ideal choice, for price/power-consumption considerations.

Anyone know anything DEFINITE about the "quad" 9600gt?

Many thanks, and I look forward to any "authorative" comments (preferably with links as proof).