mm well cant you hook up DVI adaptors to HDMI and there for you need two Quad Cards and a Dual card.
cheap quad card say £85 (tho i have got S3 Trio Quad cards but dont touch them)
so £85+£85 and a cheap graphics card to get dual.. £30 say out of the blue
£200 then you need adapters to get to HDMI.. £2 a connection so another £10
the £85 are PCI
and then allyou need for this oen would be a system with 2-3 PCI slots