Usage of round ceiling lamps in my small apartment showed their major drawback. It is low illuminance. Small amount of internal space and thermal requirements restrict the maximum power of usable light sources (bulbs, fluorescent lightings and LEDs) with E27 base. Matt glass shade also reduces amount of light passing through it. To meet my wife's claim to fix that drawback the following design with 50W LED (approximate equivalent of three 100 W incandescent lamps) was born.
Caution: be careful to avoid electric shock.

Step 1: Gather Materials and Tools

Bill of material (about 60$ without ceiling lamp):

50W LED (I prefer warm light)
LED driver
Heatsink
Screws M3
Thermal grease
Ceiling lamp

Set of instruments:

Soldering iron
Screwdriver
Threading tool
Infrared thermometer

Step 2: Lamp Assembly & LED Soldering

Remove all internals from ceiling lamp.
In the centre of metal base fix heatsink and driver. For this purpose mark and drill 4 holes for heatsink and 2 holes for driver. Then mark and drill appropriate holes on the heatsink. Make M3 threading in heatsink holes.
For LED mounting mark and drill appropriate holes on the heatsink. Make M3 threading in heatsink holes. Grease heatsink with thermal paste before LED mounting.
Mount LED and solder wires to LED according to polarity.

Step 3: Testing

Turn the lamp on and measure temperature on LED surface with infrared thermometer for 15 minutes. If temperature doesn't exceed 80C then your LED will work for a long time.

Step 4: Results

That's all. You can mount lamp on the ceiling and connect electricity.
Benefits of this design are:

Intensity Luminous: 4500-5000 lm (unbeatable value for home ceiling lamps)
Incredible power saving in comparison with equivalent of three 100W incandescent lamps
Passive cooling - no fans, no noise, no additional power supplies for fans
Long life (50W LED round ceiling lamps work for half a year till now and I hope will work much more)
Some LED drivers allow remote control of LED intensity and other possibilities
Usage of LED lens may provide even light flow in all directions