bookshelf speakers

I know that bookshelf speakers are not meant to be actually placed in a bookshelf, but I can I do? I only have room for a pair in a long bookshelf. It is actually more a ear level (sitting) bar with some books on it. No room for stands. I would like some help from you guys to shortlist a few speakers that would serve my needs. Again, the place for the speakers is a shelf about 50cm wide and therefore there is some room for a placement away from the wall. There are not other shelves on top of it. All suggestions are welcome. At this point I still don't have an expected budget, which I will define as soon as I have shortlisted the speakers.

Thanks for your help.