I suppose the main questions to be asked, are:
How brightly does the switch need to be illuminated, to have the requirement of a 3000+mcd LED?
Does it need to be
highly visible in a well lit environment, or visible from
great distances, etc?
The reason for asking such questions is, if you just need a simple on/off visual indicator for the switch, 3000mcd seems to be pretty high and maybe the LED distance/location to the light pipe is the problem, but we don't know what switch you are using or how brightly it needs to be illuminated.
An example:
On the Xbox 360 controller, there are 4 green LEDs around the Guide Button (on/off/menu) which indicate the Player No using the controller - P1 to P4.
These LEDs are an 0603 package, 0.063" × 0.031" (1.6 mm × 0.8 mm).......... a little smaller than the size of a pinhead.
I don't know the exact value used by Microsoft, but would guess from the available replacements
**broken link removed** that they may be in the ballpark of 500mcd. (I have no relationship with that ebay link, other than that of a satisfied customer. Due to their miniscule size, they are
quite tricky to handle and solder manually.)
The 0603 LED and light pipe setup used, is quite sufficient to easily be seen at least 10 feet away.
Common packages of SMT LEDs?
In order of size (larger to smaller) - PLCC, 1206, 0805, 0603 and perhaps 0402 becoming ever more popular as devices continue to shrink!!
HTH.
EDIT:
This is an 0402 package -
https://www.globalspec.com/FeaturedProducts/Detail/Kingbright/0402_SMD_LED/4017/0