Is there such a thing as a true "instant start" CFL which produces full
intensity brightness as soon as it is turned on? I am trying to find an
indoor bulb which will not require any warm up period to attain full
brightness.

I know that claims are made, but wonder if they are exaggerated or true.
General Electric, for example, actually labels their bulbs as "instant
on" but they are not 'instant'.

I also realize that colder temperatures prolong the ionization / warm up
period, but my application is for indoor use at normal 70 degree F
temperature.

Thanks for any advice.