Are there any working microturbines like described at:
http://www.memagazine.org/backissues/october97/features/turbdime/turbdime.html

I'd like to be able to buy one, but pointers to working prototypes
would also be wonderful (or information that they don't exist).  Also,
when operating how much noise do they make?  I did find one research
paper from the people at MIT, but I can't find it at the moment. 
Links to research papers, or research groups would also be helpful.

Hello again, Larry95.

At this time, the answer to your question could be summed up in
Bogart's famous line from Casablanca: "Maybe not today, and maybe not
tomorrow, but soon...and for the rest of your life!"

Both the microturbines you'd found references to at MIT's Gas Turbine
Laboratory, and the microrotary engines under development at Berkely's
MRCL, are a few years from commercial availability (or even "gettable"
prototypes).  However, given that a) both have significant funding
available from the military, and b) the commercial potential is
nothing short of phenomenal! it seems inevitable that these will be on
the streets as soon as technology/patent/marketing considerations
permit. These "microelectromechanical systems", or MEMS, promise to do
for engineering and the physical sciences what microprocessors have
done for the computer industry.

The originator of the microturbine concept, the GTL's Alan Epstein,
was interviewed by Smithsonian Magazine for an article published just
last month (July 2002).  In this article, among much other interesting
information, Epstein mentions that his primary financial backer, the
US Army, expects to see a demonstration of a working microturbine
generator within four years.  That deadline, Epstein casually remarks,
"is no problem."  At present, the pressing design issue is the
tremendous heat generated by these devices.  The article may be found
at this URL:
http://www.smithsonianmag.si.edu/smithsonian/issues02/jul02/phenomena.html

And the "Additional Resources" link at the bottom of the page will
take you to this page of MEMS-related MIT resources:
http://web.mit.edu/aeroastro/www/labs/GTL/research/micro/micro.html

UC Berkeley's Micro-Rotary Combustion Lab (MRCL), referenced in the
article found by blader-ga (see comment below) has a somewhat higher
profile, including their own website.
http://www.me.berkeley.edu/mrcl/

Although the MRCL has chosen the Wankel rotary design as its base,
rather than the gas turbine design, the end result will be very
similar in terms of its potential applications.  You'll undoubtedly
observe that the applications listed on the MRCL page are very similar
to those on the MIT MEMS page.  This article, from April of 2001,
gives a picture of the current generation of "mini" (rather than
"micro") prototypes.
http://www.berkeley.edu/news/media/releases/2001/04/02_engin.html

Case Western Reserve University's MEMS Resource unit is presently
building a prototype of the Berkeley-designed microrotary, 1.5mm in
size, according to this article:
http://www.chipcenter.com/TestandMeasurement/ed015.html

The MEMS resource offers a wide range of training and foundry
services.  You may wish to visit their site at http://mems.cwru.edu/

A good resource for information on current MEMS research may be found
at DARPA's website.  This lists current projects (50+) which have
received at least partial funding from DARPA.  Clicking on any
individual project will provide you with a one-page summary of its
current status, along with shorter- and longer-term goals.  This is
the URL:
http://www.darpa.mil/mto/mems/summaries/Projects/

The summary for the Berkeley project is here:
http://www.darpa.mil/mto/mems/summaries/Projects/University_46.html

Some similar projects on the list:

Microgenerator
http://www.darpa.mil/mto/mems/summaries/Projects/Battelle_6.html

A hydrogen-powered fuel cell utilizing MEMS technology
http://www.darpa.mil/mto/mems/summaries/Projects/Case_16.html

Magnetic power generation
http://www.darpa.mil/mto/mems/summaries/Projects/Georgia_21.html

MEMS piston engine
http://www.darpa.mil/mto/mems/summaries/Projects/Honeywell_25.html

Power generation with chemical fuel
http://www.darpa.mil/mto/mems/summaries/Projects/Massachusetts_34.html

And this is just from the top portion of the list!  None of these
projects are anywhere near "ready for prime time", but it seems
certain that their commercial impact will be huge.

Search strategy:

The links provided below by Blader-ga saved me some initial digging,
by providing some useful keywords. The following searches, and the
connections I made from these search results, provided all the
information given above:

+MIT +microturbine
"Micro-Rotary Combustion Lab"
+"Case Western Reserve University" +MEMS

A simple search on the keyword "MEMS" generates a ghastly quantity of
hits.  You may find this page, at Cornell University, to be a useful
resource for further digging:
http://people.cornell.edu/pages/akt1/memsmain.html

Thanks for another great question.  I'll be reading up on this stuff
for weeks, just for my own interest!

Dear larry95:

This isn't enough research to justify an answer, so here it is as a
comment:

The MIT research group mentioned in the article is here:
http://web.mit.edu/aeroastro/www/labs/GTL/

Unfortunately, there isn't too much info on it, but there's a list of
research abstracts:
http://web.mit.edu/aeroastro/www/labs/GTL/pubs.html

There's also a reference to some research at UC Berkeley doing a
similar project in this article:
http://www.ammagazine.com/CDA/ArticleInformation/features/BNP__Features__Item/0,2606,27001,00.html

Best Regards,
blader-ga