in a word .. no
Your biggest obstacle is the fact that the sky signal is scrambled. So only sky boxes can receive it. So the only way of descrambling that signal is with a skybox, and that skybox by its very nature only receives 1 input, so can then only send one that 1 output
the only thing you could do, would be to use the RF output of your skybox, and output that to 4 TVs ,but they would all have the same channel. You could use sky senders to use sky remotes and change chanells but they'd all have to watch the same thing
and i think sky know how many LNBs your using, so you cant fit your own quad LNB, buy 4 skyboxes and not tell sky. They control how many outputs you get.
So its skys own multiroom (£10 / month per box)
or they all show the same channel.