After testing several LED bulbs I have finally found one with which I am completely satisfied.
Weanas® 4x G4 Base 48 LED Light Bulb Lamp 3 Watt AC DC 12V/10-20V Warm White Undimmable Equivalent to 20W T3 Halogen Track Bulb Replacement 360° Beam Angle
http://www.amazon.com/gp/product/B00IJ7APY2
These are under $2 including shipping. They are warm, wide voltage range, do not cause any interference for me, and they are about as bright as the 10W halogens. I know the "specs" claim 20W equivalent, but that is not my assessment. They also draw about 1.6W, not the 3W that is claimed.
These are G-4 two-pin base and they plug directly into most of my lights. I do have some lights that use a wedge base and I bought some PWB adapters and soldered these lamps to them. They work nicely.
Now we can have lots of lights on, not live in a dark cave, and not suffer a big power draw.