If you don't have too many plants you are trying to light then a high wattage CFL might work OK in a shielded clamp fixture. One of the things important about purchasing fixtures is making sure the available light from the bulb is directed and shielded correctly - otherwise a high percentage of the available light given off by the bulb can be wasted - going off into non-orchid directions. You can never "harvest" 100% of the available light, but want to maximize as best you can. Places like Lowes and Home Depot usually only sell the CFL's up to tungsten bulb equivalents - maybe something around 50-60 watts (150W equivalents). If you can go to a place in your area (or online) that sells higher wattage you can probably get 2-3X that and still fit it into a conventional inexpensive clamp lamp fixture. If this concept sounds do-able for your situation we can kick around the idea some more either via this thread, pm or email. Good luck!
mike