I think it maybe cheaper to partition a cubicle off and just have a door, with door and door curtain, as Gandi says it doesn't have to be totally light tight but positioning a door that doesn't have a direct light, just a then normal lined curtain would suffice, would make it a whole lot easier, depends how big your room is at the mo and can you keep a permanent feature, as your description suggests it a quite large room, dont forget you also need good ventilation