Low budget 4 cameras mixed live ?

Hi,

I have a high budget solution to stream a live event mixed from 4 cameras using the Sony Anycast switcher.
But I can't achieve a good alternative for a low budget solution...

I was thinking of high quality Pan/Tilt/Zoom wireless surveillance IP Cameras. Something likethis one. There is even a free software to switch from feeds but I can't find how to make it work with FME... But it's possible that I am searching in a wrong direction…

Does someone managed a complete low cost multi-cameras solution and could guide me ?
;-)

Thanks for your help !
Paul