I doubt it.  I think the typical 1-2 year old hollowfibre pillow will be
saturated with sub-micron sized mite allergen particles along with the skin
scales and the mites, I doubt that vacuuming the surface will pull it all out
of the wadding, although it will reduce it to some extent.  Sub-micron
particles in particular adhere to surfaces by molecular cohesion and the
only way to remove them is scrubbing, so vacuuming the pillow surface is
likely to be only partially effective.

It'll be interesting to hear if you can see mites through the microscope.  
An electron microscope would be best.  Perhaps a better test would be a
chemical test for the mite allergen in extracted dust? Even if you can see
the mites, will you be able to see the allergen particles which are down
to 0.5 microns in size?  

I found this study:

http://bmj.bmjjournals.com/cgi/content/full/313/7062/916

which showed that allergen load in "hypo-allergenic" synthetic pillows
was no better than in feather ones.  Interestingly they say in their
discussion that synthetic pillows may release volatile organic compounds
that may exacerbate the allergic response, so perhaps feather pillows
would be better in that respect; but of course feather pillows are a lot
more expensive.

The synthetic pillows are extrememly cheap nowadays in supermarkets;
for example, I just bought 2 pillows for 2.50 UK pounds which is about $4.20.
If I change them three times a year that's 7.50 UKP or about $12 per year.
That's probably cheaper than the cost of washing those same pillows once
a month at 60 degrees C, particularly in England where electricity and water
charges are high.

Similarly a king-size duvet cost me 10 UK pounds (bought one last month)
or about $17, so again it's cost effective to replace it 3 times a year.
It actually costs more to wash/dry the duvet in my local launderette than
to buy a new one!  Of course these are the cheapest pillows/duvets available
from large supermarkets but they work perfectly well.

It's arguable that my approach is somewhat wasteful, I guess I could
give the used bedding to a charity shop instead of throwing it in the bin.

I would like to find out how rapidly the mite population builds
up in new pillows/duvets and how quickly the allergen load builds up.
I've replaced mine every 4 months or so to keep costs down, and subjectively
in terms of symptoms that works, but I don't know how long it takes the
mites to build up to deliver enough allergen to produce the allergic response.  
I'd be very interested if anyone knows of any studies on this.  Of course
I also have the air mattress and a hard floor covering so hopefully there
aren't many mite populations in  the bedroom to re-infect new bedding.  
It might get repopulated faster if the bed had a normal mattress full of mites.

Tony