Good evening all..
Another idea that might be useful in this context is Win Wenger's 'gravity pose' pre-sleep meditation tactic.
I've added an excerpt from his _Beyond_OK_ (highly recommended book splicing ImageStreaming and energy skills) describing just that.
In my experiences using this system, around 10-12 minutes meditating just before sleep chops a good chunk off the time I need - I just wake up an hour or three earlier than usual. Make sure you actually get out of bed then when you try it 
I've yet to try it myself with a polyphasic sleep system and it looks promising.
--Michael
PS: Here's the drill.
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Sleep-Need Saver:
An interesting new application of the "gravity position." To meditate
with whatever process for 10-15 minutes, in the "gravity position," just
before going to bed--and then going straight to bed to sleep--appears to
satisfy 2-4 hours of sleep-need each evening that this is done. The
effect appears most pronounced when accompanied by noise-removal
breathing.
The Gravity Position:
Lie flat on the floor, no pillow, hands and arms loosely by your sides.
Comfortably support your feet and lower legs on the seat of a chair,
supported as far up as the backs of the knees.
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Sleep-Need Saver:
An interesting new application of the "gravity position." To meditate
with whatever process for 10-15 minutes, in the "gravity position," just
before going to bed--and then going straight to bed to sleep--appears to
satisfy 2-4 hours of sleep-need each evening that this is done. The
effect appears most pronounced when accompanied by noise-removal
breathing.
The hypothesis is that the first few hours of sleep are heavily invested
in re-aligning the circulatory system after the day's upright
verticality--and by satisfying that need for circulatory readjustment
and doing so rapidly, meditating in the gravity position satisfies a
large portion of sleep need.
The above hypothesis cannot, however, be the full explanation since the
effect disappears if one does not go to bed immediately afterward. Also,
little if any of the effect appears if the meditation is done without
the "gravity position" or vice-versa.
This phenomena, first observed in June, 1978, is one of many questions
raised during Psychegenic investigations which are much in need of
further research.
The Gravity Position:
Lie flat on the floor, no pillow, hands and arms loosely by your sides.
Comfortably support your feet and lower legs on the seat of a chair,
supported as far up as the backs of the knees.
This gravity-aided brain-circulation-enhancing position we prefer to the
Yoga headstand, not only because it is so much easier to perform, but
because it lets old blood out of the brain while encouraging more new
blood in.
(This gravity-aided position has also become a favorite _general_
meditating position of a fair number of some practitioners of
Psychegenics since its development late in 1975, because it feels so
very refreshing.)
Other Advantages of the Gravity Position:
Although the Savassana Yoga position is supposed to be the ideal
position from standpoint of encouraging best and freest flow of
circulation of blood and energy, this gravity position, like the
Savassana except for the feet-and-legs up, appears to be fully as free.
The gravity position is much easier upon pelvic and lower-back
structures than are either the seated or the flat-on-floor version of
Savassana--excepting pregnant women, kidney disease, and some few
specific forms of back disorder.
Whenever need be, the gravity position can be sustained comfortably for
far longer than any othere meditative position except possibly the full
lotus (and does not present the difficulty which most people experience
in attempting the lotus). Whereas some do experience loss of circulation
in feet or legs while in lotus, this does not occur with the gravity
position.
On really deep problem-solving probes, for example, occasional
Psychegenicists have gone as long as three hours in the gravity
position, without any discomfort.
