Knight Optical has a family of extremely strong Fresnel lenses, F# = 0.2.
15 mm lens needs to be just 3 mm above the die to focus on it.
This leads to very high light collection - 82% of all light gets captured to the beam.
They are available in many sizes from 15 mm to 125 mm.
High collection is close to high efficiency but is not all of it. The lenses are not AR coated stock (but manufacturer offers such option). They’ll suffer pretty high reflections at the peripherials unless coated.
Will they throw?
1. Fresnels suffer from reflections off the peaks, that reduces throw
2. Strong lenses are worse collimators than weaker ones
3. Fresnels have larger clear aperture than regular lenses of the same diameter - giving them natural 23% throw advantage over a standard aspheric
4. These are “precision” grade items
So….I have no idea if they throw but I wouldn’t expect them to have record-breaking potential.
But they have other advantages:
- super short zooming movement makes head design easier
- little effort to adjust focus
- head can be very compact
- the lenses are very lightweight
So…interesing base for a small, light and efficient zoomie. 
ADDED: NTKJ has a similar line, from 15 to 250 mm:
At 50+ mm they offer even higher pitch. And they have negative lenses of the same strength as well (but only 25, 50, 100mm).