Clone desktops across multiple video cards/adapters?

So here's what I'm trying to accomplish: I would like to clone the following setup so that my brother (who lives overseas) and I can log into our slingbox remotely and watch WMC7, while still allowing myself and anyone who is at home to watch WMC7 normally on the HDTV

Onboard Video HDMI output to Flatpanel HDTV
Discrete Video (video out) Component to Slingbox Pro HD

Hardware:
Mobo => Asus p5n7a-vm (onboard geforce 9300 w/ vga, dvi, hdmi, displayport out)
Discrete VGA => Gigabyte GV-NX86T256H (Nvidia 8600gt with dual dvi-i & component video out)
HDTV
Slingbox Pro HD

A little background:
I've had issues going dvi-hdmi to my plasma tv. For some reason my tv has compatibility issues with the 8600gt. Sometimes it works fine with it using the dual output (dvi & video out) and other times I can't even get the machine to boot. Recently the latter was occurring nonstop. Then afterwards my mobo burnt out and i opted to switch a matx board to move my system into the tv stand (which I had been meaning to do for quite a while anyways). My issue now is that I am unable to clone the onboard video and the video out from the discrete video. Is there any way to do this?

Thanks in advance!
Kelvin

Is there a software solution? Maybe some sort of multiple adapter manager?

hm thanks! i'll take a look a report back.

@ soitjes -
unfortunately the software requires multiple pcs, and does not work within a single system

@Nvmarino -
that's actually how my system was setup for a long period of time until I started having my hardware issues. I do have a 360 and have considered setting it up as an extender. the main reason i haven't yet is because i have some plugins setup (e.g. hulu desktop and boxee) that only run thru MC and not extenders. however, since it seems that at this point i'm limited on options, so that might need to be the next step. there are RGB to YPrPb converters out there but the cheapest i've found its around $70.

does anyone know how WMC7 performs over RGB? Are there issues playing bluray via 3rd party software (i use arcsoft total media theater) (also have Anydvd).