Bookshelf Speakers on Bookshelves?

I'm putting together a system where space is very limited and I'm wondering if anyone here has ever put bookshelf speakers on actual bookshelves as opposed to speaker stands? Would be interested in all responses and in particular any results with Sound Dynamic's 300ti's. Thanks to all.
I just put in a pair of Bohlender Graebener Z-1's in my bookcase they are the best I've had in their to date. It is supposed to be taboo to put a rear ported speaker against the wall much less in an inclosed space such as a bookcase but I think they sound great with plenty of body and fullness to the music.

Check out the Z-1's for $350. The treble is nice and airy and it is well balanced. I've read that the midrange is a tad recessed but if that's so I like it. I'm begining to think that I like a midrange that is not so detailed and "attention getting". The more speakers that go through my systems the more I like a smooth, easy going sound. The Z-1's fit the bill beautifully.

This link shows how I have the Z-1's set up.

Assuming you can get the right height/position;

Isolate the speakers from the shelves with blu-tak and pack them with books on all sides so that you absorb the rearward LF radiation whilst creating an even surface flush with the baffle for forward radiation (half space).

In a more thorough arrangement, you could surround each speaker with a thick frame of medium density mdf material and some foam padding (to help absorb rear LF energy & best if this is an integral braced part of the shelving).

You will have a reasonably close equivalent of a soffit mount(an in-wall speaker configuration used in studios) and a practical place to keep books. Not perfect but probably better than on a stand close to a wall, which gives LF energy cancellation from rear wall reflected energy.
You are of course right as far as height goes. I'm building a listening station to house everything. This is going to be located in a smallish area and not for real critical listening, just an enjoyment feature as I work. What I'm really trying to get from this thread is specific speaker models that other people have used. What sparked the interest was the visit to a record store and an older model Harbeth P3s (NOT 3/5 s) were being used on bookshelves to demo records. While the electronics were hardly first class, I couldn't help to wonder how a small system would sound in my workspace. Certainly it would be better than the now popular ipods and computer based systems that adorn many work areas. Thanks for the input.
There will be a noticeable lower midrange boost that makes singers sonud like they have chest colds if the speakers were not designed for on-wall placement.
Wilson Duette's
Agree with Oneobgyn. I recently heard the Duette's (I also own a pair) on a flimsy Ikea bookcase in a Dallas shop (set up that way to prove a point). These are excellent speakers for stands and actual bookcases.