What monitors sound OK on a bookshelf?

I bought a new house with a living room that has beautiful bookshelves and layout complications which restrict my ability to use stand mounted monitors for the front channels. I want to buy some small speakers that will sound OK sitting at ear level in the bookshelves. I love Harbeths, for example, but have no idea how they would sound in this setting. Any thoughts on good options?
Wilson Duettes sound great and look great too.
Try Genelec 8040, 8050 or Focal Twin 6 Be - all are designed to sit on a studio meter bridge and should sound great on a book shelf.

I have the Genelec 8020b as office desktop speakers and they are without parallel for their size (if you like precise sound) - for a bookshelf you will need a bigger model Genelec.
Thiel SCS.
I have Harbeth PSESR's on an entertainment unit, close to the wall. They sound incredible - no port, easy to place...
Spendor 3/5 with its sealed woofer would fit the bill!
Omega Super Six Alnico Monitors. I had a pair and then upgraded to the Super 8 XRS Alnico. Louis could build them with the port in the front to suit your needs. Give him a call (203) 847-2800. Custom design,great sound, reasonably priced, and 30 day money back gaurantee.
Joseph Audio Rm7si's
Basic rules are to have a sealed cabinet or at a minimum a front facing port. Other things to look for in reviews are speakers that are mentioned to sound good close to the front wall with a narrow dispersion pattern.

One thought would be Tannoy concentric monitors like the revolution D6.
In my experience, Silverline Minuets are worth a look. They're rear-ported but are largely indifferent to placement and can benefit from rear-wall reinforcement. A couple of others monitors that are frequently recommended for use in a bookshelf are Rega R1 or RS1 and Von Schweikert VR-1. I haven't heard either, but many people swear by them for this application. Some sealed or front-ported models are tricky because they're designed to be used in free space. The question comes up pretty often; a search on the topic would give you additional ideas.
Only those that have a front vent, or no vent at all.