That bulb is a PAR30 which is 3.75 inches wide. The brighter PAR38 is 4.75 inches wide. They are also correspondingly heavy.
They are also available in north America but does not come with UL or CSA or ETL listings. The CE marking on these bulbs are only good for 230V countries and NOT accepted in the USA or Canada. This is very important because if the bulb causes a fire that burns down your house, your insurance company would not pay if you are using non listed products.
Led lamps to replace 100 watt incandescent are not yet readily available, the brightest that I have seen are these
http://www.ultraleds.co.uk/household-bulbs-screw-240v-bulbs-c-92_110.html
Only equivalent to 75 watt though.
Although at the top of the page these are refered to a 240 volt lamps, they are in fact multi-voltage 100/240 volts and therefore suitable for USA 120 volt supplies.
CFLs are not recommended for use upside down, especially in heat trapping downlights. They are very likely to catch fire!!!
Alternativly, re-consider CFLs, for reccesed downlights be certain to get the reflector type.
Most of the light from regular CFLs is wasted in reccesed lights.
LED bulbs are dim compared to incandescent and CFL bulbs. So they are not good for replacing multiple 100W bulbs.
Here is a 40W incandescent left compared to a Philips MasterLED 7W LED right.
I find the best way to reduce heat is to not be lazy and light up a room to the max.
First I only light up the room to sufficiently not run into walls and doors nor trip over the furniture. Here is my hallway lit with a 2W Cree. The other light on the left is a 3LED nitelite. That does not light up anything.
Then I use dedicated lamps for spot lighting. Desk lamps for keyboard and desk lights. Headboard lamps for reading in bed.
I am also using 2W Crees but the light output is marginal. The 7W Philips bulb which should be in general release now might be a better choice.
What kind of light fixtures are your 100W bulbs in?
Table/floor lamps, (13W-23W CFL)
Torchieres, (23-40W CFL)
Ceiling flush mount fixtures, (23W CFL or Evolux)
Ceiling semi flush mount fixtures, (2*13W CFL or Zetalux or Geobulb)
Pendant fixtures, (no good replacement)
Recessed fixtures, (no good replacement EDIT Cree LR4 & LR6 /EDIT)
Desk lamps & headboard lamps. (Zetalux or Geobulb or MasterLED. Due to UV emissions I do not recommend CFLs for close in lighting. this recommendation may also apply to table lamps depending on how close you are to the bulb.)
The Philips MasterLED should be in available in July. Got mine at Home Depot. Cost me $29.95 CAD.
evolux $79.95 + shipping.
zetalux $49.99 + shipping.
Geobulb $99.95+ shipping
Geobulb at Amazon $84.84
AFAIK all the above bulbs are UL listed.
I do not recommend multiple 5mm LED based bulbs as they tend to dim to useless in 6 months. Some do not last 2 weeks.
Remember LEDs are very directional so you have to point them at where you need light.