For us the DVI bandwidth was the limiting factor to deliver 40-50 views at reasonable framerates (besides raw GPU computing power), so our display actually had 8(!) DVI inputs. That also gave us a natural interface to add distributed rendering, supporting up to 8 GPUs for rendering. In most cases though, one monster PC with 3 GPUs and 5 DVIs was enough to produce interactive framerates.
For us the DVI bandwidth was the limiting factor to deliver 40-50 views at reasonable framerates (besides raw GPU computing power), so our display actually had 8(!) DVI inputs. That also gave us a natural interface to add distributed rendering, supporting up to 8 GPUs for rendering. In most cases though, one monster PC with 3 GPUs and 5 DVIs was enough to produce interactive framerates.