The original question on this thread was about why it is not possible to use the perfect continuous tenses in the passive.
It is possible to use the perfect continuous (progressive) tenses in the future. Here are several examples from the New York Times Archives:
"¢ Mr. Hussein has been being
held in American custody by a team known as Task Force 134 at Camp Cropper, near the Baghdad Airport. Published: December 29, 2006
"¢ Now, though, it has been being
hauled out for display at the place that was its original destination: the original New York City Building, which now houses the Queens Museum of Art, in Flushing Meadow Park. A seven-piece section comprising the New York area is on display at the museum through Feb. 12. Published: December 4, 2005
"¢ According to Rapiscan, more than 90 percent of passengers searched while their machines have been being
tried out at Heathrow Airport near London have chosen the backscatter over a pat-downPublished: October 9, 2005.
"¢ ''There's no excuse,'' David Neustadt, a spokesman for Mr. Hevesi, said on Friday. ''It should have been being
paid all along, but the most important thing is it will be paid.''Published: September 23, 2006
"¢ The biggest hindrance for the Treadaways may have been being
strapped together -- with everything from a rock-climbing harness to prosthetics -- for long periods of time. ''It was a bit annoying anytime you wanted to go to the toilet,'' Luke Treadaway said. Published: July 16, 2006
"¢ ''It is a very common thing, not only in Essex but throughout England, that churchyards are being closed simply because they have been being
used for such a long time,'' said the vicar, the Rev. Richard Salenius. Published: April 13, 2004
Here are examples appearing on other sites:
"¢ I have been being
paid on the 10th and the 25th now since I've been with this company. We were always paid on an earlier day if the 10th or the 25th fell on ...http://www.laborlawtalk.com/showthread.php?t=146664
"¢ For that matter, advances have been steadily been being
made in medical imaging as new developments have been being
made through the past century! ...http://qd.typepad.com/37/2005/10/the_motive_for_.html
"¢ "Well, there isn't much left, because that money has been being
spent for months now." was my answer. http://www.robshouse.net/hasbeenbeing
Now, the topic of the passive used with a perfect progressive has been addressed on several language discussion sites. Here is one example:
"¢ Suppose now that what we commonly call a passive construction in English contains a perfective aspect, and that aspects can be combined. Then we can construct verb phrases with the following aspects:
The car was cleaned. | perfective
The car was being cleaned. | continuous + perfective
The car had been being
cleaned. | perfective + continous + perfective
The last combination will accordingly be restricted to contexts in which it is important to convey (in this case) that an event with a result was ongoing in the past but is completed now. Usually, we don't need to be quite that specific and we emphasize either that an event was ongoing or that it is completed. http://listserv.linguistlist.org/cgi-bin/wa?A2=ind9108a&L=linguist&P=1370
Of course the passive with all progressive tenses exists as seen in the examples above.
It is true that with some tenses, its use is not frequent and in many cases may be stylistically awkward. However, there is no doubt that these tenses exist and are sometimes used very accurately to describe an ongoing situation.