The big issue that you will see with a space that SHORT is heat. HPS is better than MH for flowering, but any HID will throw more heat than you will be able to deal with in the 2' of vertical space you have between bulb and dirt.
Look into T5 flouros (google 'new wave t5' for a good example) or a larger wattage flourescent bulb. They are out there, and they work. Best of all, they run cooler than HIDs.
If you DO decide to go with a HPS, be prepared to spend almost as much on ventilation/exhaust as you did on the light.
stinkyattic Reviewed by stinkyattic on . will this work? our growing area is around 4' tall , 2' deep and 2' wide would this light be suitable for the space? with 3-4 plants 250W METAL HALIDE HID HIGH INTENSITY DISCHARGE LIGHT on eBay, also, Lights Lighting, Building Materials Supplies, Business, Office Industrial (end time 30-Mar-08 10:22:44 BST) they are just 7 days into the flowering, and have been under a 75w fluorescent. new, so help would be appreciated . we are just doing this for a bit of fun, on the cheaper side of things Rating: 5