Here are a few. I am guessing that you can find at least of these brands in your local tropical fish store. I know I can.
http://www.reefgeek.com/lighting/T5_Fluorescent/Bulbs/39_Watt/39W_6500K_Daylight_T5_HO_Fluorescent_by_General_Electric
http://www.reefgeek.com/lighting/T5_Fluorescent/Bulbs/39_Watt/39W_Midday_Sun_T5_HO_Fluorescent_by_Giesemann
Aquarium Lighting T-5 HO Florescent Bulbs: AquaticLife T5 HO Natural White 6,000°K Fluorescent Lamps
Aquarium Lighting: T-5 Fluorescent Bulbs: Hagen Life-GLO T-5 HO 6700°K Bulb
Aquarium Lighting HO T5 Fluorescent Bulbs: Zoo Med Laboratories Ultra Sun Super Daylight T5 HO Lamps
Amazon.com: Wave-Point Tropical Wave 39-Watt High Output T-5 Lamp: Pet Supplies
http://www.reefgeek.com/lighting/T5_Fluorescent/Bulbs/39_Watt/39W_6500K_Daylight_T5_HO_Fluorescent_by_General_Electric
http://www.reefgeek.com/lighting/T5_Fluorescent/Bulbs/39_Watt/39W_Midday_Sun_T5_HO_Fluorescent_by_Giesemann
Aquarium Lighting T-5 HO Florescent Bulbs: AquaticLife T5 HO Natural White 6,000°K Fluorescent Lamps
Aquarium Lighting: T-5 Fluorescent Bulbs: Hagen Life-GLO T-5 HO 6700°K Bulb
Aquarium Lighting HO T5 Fluorescent Bulbs: Zoo Med Laboratories Ultra Sun Super Daylight T5 HO Lamps
Amazon.com: Wave-Point Tropical Wave 39-Watt High Output T-5 Lamp: Pet Supplies