LED bar on a powered pendulum?

The biggest drawback to LEDs is still their high cost.

The biggest benefits are the long life, the ability to target specific wavelengths, the low relative heat, and - in some cases: to choose or change the viewing angle.

I have a 120 watt unit with 1 watt LEDs that does OK for my small 2' X 2' garden, but does not seem to have enough intensity or spectrum without adding CFLs. Looking at 10w LEDs for a DIY light is appealing, but very hard to justify the cost for the LEDs, heatsinks and drivers.

Here is my thought: Instead of a LED square with say 16 each 10 watters, use a tightly focused LED bar with maybe 6-8 each 10 watters that may cover a 24" X 6" swath and attach to a pendulum motor of some sort to swing the bar back and forth to cover the whole garden.

Obviously the plants would need to be arranged in some sort of V or U arrangement to match the swing arc to get nearly equal lighting.

Would probably still use some minimal supplemental T5 lighting to keep the plants bathed in light between the high intensity LED 'baths'.


Advangtages:

Minimal cost and complexity compared to spinning lights.
Less than half the initial cost, heat, and electricity of static LED lights.


Disadvantages:

Added cost and complexity of drive motor.
Would not work well with a single plant or a flat scrog/sog.

A similar idea for a single plant would be to hang the LED bar vertically and put the plant on a rotary Christmas tree motor. ($25 for a unit with 20 pound capacity?)


Thoughts from both engineers and plant physiologists?

"use a tightly focused LED bar with maybe 6-8 each 10 watters that may cover a 24" X 6" swath"

3 watt LEDs are already past the thermal design of my 2-foot T8 bars. The sheer amount of heat from a 10w LED would require either a VERY LARGE surface area for passive cooling, or active cooling. Active cooling would guarantee a long service life.

Swinging action might be done without power - remember the wind-up baby swings? If we had a mechanism that could keep swinging for 24 hours after a full wind up, no bother with power! Pendulum action is a good idea, but a wider swing will necessitate a longer extension, thus lots of overhead room will be needed.

I've been trying to work on a rotating LED bar for a while, the biggest problem is a reliable slip ring. Good ones will cost almost as much as the LED bar itself, making them prohibitively expensive. The ones in a rotating Christmas tree stand might work, but I'd worry that at that price it would fail prematurely.

Maybe like a crank gear attached to an r/c motor to move the bar side to side along a track? I don't know, just popped into my head like a cheap DIY light rail...