I own an ACER Aspire 7530G with a Geforce 9400M HybridSLI adapter (at least that what's advertised on the laptop stickers).
nvidia-settings reports a GeForce 9100M G and a GeForce 9300M GS.
lspci: (see attached link "lspci -vvnn" for the whole output of said command)
02:00.0 VGA compatible controller: nVidia Corporation GeForce 9100M G (rev a2)
03:00.0 VGA compatible controller: nVidia Corporation GeForce 9300M GS (rev a1)
There is no external button or BIOS switch to swap which card is used - this happens automatically with Vista and seems to be handled by the nvidia driver or Vista power management.
LiveCD and booting without the proprietary driver works, but is very, very slow.
When booting with the proprietary nVidia driver set in xorg.conf, xorg throws an error in xorg.0.log (See links). Only a black screen can be seen.
When setting BusID to "PCI:2:0:0" in xorg.conf, you get a working X with hardware acceleration and all that, but only using the slower of the 2 cards (afaik). See Links for Log.
Using BusID PCI:3:0:0 doesn't work but throws a new error. (See my forum post at http://ubuntuforums.org/showpost.php?p=6674183&postcount=1 or the whole output at Links)
Xorg.0.log, nvidia prop. driver without changes to xorg.conf: (Throws error at the bottom)
Xorg.0.log with BusID "PCI:2:0:0": (Works)
Xorg.0.log with BusID "PCI:3:0:0": (Throws errors)
ASDS.dsl is attached to this post.
Please note: This is from a working boot with BusID "PCI:2:0:0" and the proprietary driver.
If you need one with other options, just ask. :)
If any more information is needed, just ask.