a little help hdmi splitters, switches, and convert to dvi

hello all
im trying to set up my system. i have a comcast cable box, a ps3 , xbox 360, and two computers. that i want to put to, two 19' monitors and a 42' lcd. having everything interchangeable. my plan is to spite the cable box, ps3, and the 360, to 4 outputs, 3 of which will go to the 5-to-1 hdmi switches and then to the monitors and lcd, and the 4th go to the Onkyo HT-S5100 7.1 Channel Home audio System. then have the computers spite 3 way, with all going to the 5-to-1 hdmi switches though the dvi to hdmi cables. now from the 5-to-1 hdmi switches, having 2 of then going to the 19' monitors via hdmi to dvi, and the last 5-to-1 hdmi switch to the 42' lcd via a 20 foot hdmi cable.
any advice anyone can give to me about what splitters, switches, or cables to buy would be a great help

This might get you in the right direction, at least the video portion. I chose to not use the 5x1 splitter because you mentioned that you wanted to do things simultaneously. The 4x2 is a matrix switcher meaning you can route any of the 4 inputs to any of the 2 outputs. In this case it is setup so that either of the computers can add to the other 3 sources, but both monitors will view the same image. I took into consideration that your monitors were DVI. All portions in Red are DVI. I also assumed that the 3 HDMI sources were in the same room as the lcd tv and the 4x2 switcher and 2x1 switcher. Therefore the longest lays are from the switchers to the additional room.

By the way all part numbers are at monoprice

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