I use a ZOO MED dual deep dome light fixture for my basking bulbs, with two heat lights in it. It has one 100 watt bulb to push a bit of heat down through the cage to keep my chameleon comfortable, with a branch below it about halfway down through the cage to bask on if he wants. I also use a 60 watt in the other side of the dome fixture, with a basking branch about 6-8 inches below the light. The higher-up basking spot is warmer than the other, so that way he can choose what he wants. The bottom of the cage runs about 70 degrees still, so he has area to go down there and cool off a bit if he chooses. I have two heat bulbs because - just in case one of the heat bulbs goes out during the day (like I've had TWO do before, both when I wasn't home). If one of them goes out, he still has the other providing heat, and will just have to move himself to a different branch accordingly. That way, he will never get cold. I've came home before, twice, in the evening when I get home from work, and I've found his heat bulb to be not working and he would be curled up looking cold under the UVB. So I got a different light fixture for the UVB bulbs (I was using 1 heat bulb and 1 UVB bulb in the dual dome fixture at first), and now use the two different basking bulbs in the dual dome instead. I have one of the Exo Terra Light Brackets holding my dual dome up, so I can just move the fixture a bit up or down if it gets too hot or too cold. I also have a bunch of different wattage bulbs on hand that I use for lamps and such elsewhere too, so if I ever need to switch out a bulb for some reason instead of lowering or raising the light bracket, that option is there too.
The light with a dimmer is a good idea too if you only want to go with the 1-bulb route. I actually have that exact same 8.5" Fluker's dimmer heat lamp that
@JGuinan007 posted a link to, but I got mine at Petco during one of their 50% off sales a couple weeks ago, and I also had a promo code I found online, so I got it for $4.76 total.

They actually sell that same Fluker's dimmer lamp in another size as well. The 75 watt max is 5.5" wide. The 150 watt max is 8.5" wide. I use mine as the heat lamp on my insect table for some of my insects that require a bit of heat. The 8.5" wide with a 100 watt bulb in it at the moment, able to be dimmed to control heat, works perfect with all my insect jars. I hang the light above and slightly off to the side of the table and just place some of my bug jars a little closer to the light that require more heat, and place others a little further away. I use the dimmer feature when temps go up or down, which usually stay pretty consistent in my house (until summer when I open windows, that is...)