If 200' is the outer limit of your lighting needs I'm wondering why bother to put them on the roof at all? I'm assuming that the 200' requirement is due to trees. The whole point of a high mounting is to get the light further out ahead of you. I'd think that for 200' that you could easily do that with a top of front bumper location and avoid smacking the lights (be they cheap or not) with tree limbs (not to mention not adding them to your frontal area).
For up high I've found that the so-called "Euro" or Driving" beam is a better option than the pencil beam. The range is very close, but the Euro/Driving beam has much more lateral light distribution.
My personal RoT: The closer the light is intended to illuminate, the lower it gets mounted.
When mounted up top, and projecting downward, the light fills "holes" that are left by low-mounted lighting. The low mounted lights leave a shadow behind any high points on the trail. When the lights are higher than your eyeballs, it projects down and fills the hole. This allows you to determine how deep the holes are, or what might be in them, before you get too close.
The only disadvantages I've seen are the risk of damage from trees, glare on the hood and windshield, and glare from atmospheric conditions. All are manageable.
Glare on the hood and windshield is easily controlled by shields such as Antichris posted, or by moving the lights back from the edge of the roof a bit, which is what I did. I have zero glare.
Glare from atmospheric conditions is easily controlled by turning them off if required, and leaving you no worse off than if you didn't have them.
Damage from trees...well... I haven't had a problem yet, but some people can break anything so... <shrug>