Speaker suggestions

I have Silverline Sonata II's and recommend them. While they are rear ported, the base is not boomy. Very good for female vocals and jazz. They also give you excellent flexibility from an amplification standpoint in case you want to experiment with SET amps down the road. Gershman would also be worth of having on a short list.

I highly recommend you audition the DeVore Fidelity Gibbon 8's. They're front ported and the retail price is $2,850. I have them in a similar-sized room and configuration as yours, though mine are a little closer together. Here's a 6moons review:
http://www.6moons.com/audioreviews/devore/gibbon8.html

Sounds like you would be best served by near field monitors - move your listening position away from the back wall if you can. Bass is generally boomy if you sit close to the rear wall opposite the speakers

If a rear-ported speaker is tuned appropriately, there's no reason why it can't be used close to the wall or even in a corner. Audio Note speakers are designed to take advantage of boundary reinforcement from a corner, and they're rear ported.

You might try lowering the tuning frequency. You can do this by either lengthening the port or decreasing its diameter, or both. I've never tried this, but here's what I suggest:

Buy a piece of PVC pipe from Home Depot whose outer diameter is slightly smaller than your port's inner diameter, so it will slide inside. Cut it to roughly the length of your port (a little longer is okay, as you will probably be trimming it later). Wrap electrician's tape around the outside of the PVC pipe at one end (the outer end), enough to get a snug fit inside your port. This will lower the tuning frequency, hopefulling transforming what once was boomy bass into deeper and tighter bass. If the bass is diminshed too much, that means the PCV pipe is probably too long (tuning frequency too low) so shorten it some and try again.

A cardboard mailing tube will also work. Or a bunch of plastic drinking straws cut to length, tightly packed into the port until they deform into a hexagonal pattern and friction-fit in place. You'd probably have to remove a woofer to do the drinking straws though, as until there's enough of them to friction-hold in place they have a tendency to fall inside the box.

The tradeoff is, at high volume levels you'll get more compression in the bass region (less impact) due to the reduced port diameter. And at high volumes you'll probably get turbulence that can cause port noises (though it's possible that the tightly packed drinking straws may actually reduce turbulence; I'm just not sure). Will these tradeoffs be audibly significant? Only one way to find out.

Duke

I have tried a pair of Gershman (RX-20 borrow from a friend) in my small living room. They sounded quite booming, they have rear ported and the bass go quite deep at 20hz compare to size of the speakers. I moved them to basement, with lots of room they sounded really good. I ended with Maggies 2.6r for the basement system and the living room I got a pair of Duntech Opal front ported they sound really nice, and Duntech have seal box and front ported design make the speakers quite easy to set up in any rooms and the bass seem always right. Check out my living system pictures, my room is a bit smaller than your room and also check out these Duntech at http://www.duntech.com.au/images/all.html

They cost around 3k to bring over from Aus. but really worth every penny.

Good luck.

Sfar, what are you using to power the Devores?

Mezzrow, I'm using a Simaudio Moon I-5 integrated with the Devores. It's rated at 70 watts into 8 ohms and drives them very easily.

Mezzro - a would try to locate a pair of Gradiant Revolutions for this application. They are resolving, and have the ability to "tune" the lower frequescies depending on placement within the room and rear wall that makes them a good choice for your application. Problem is - there are very few dealers of this fine line of speakers, so auditioning might be a chore. Good luck!

My room dimensions are similiar. I have Von Schweikert Jrs., also on either side of a cabinet and very close to the wall. They sound really good and can be had used for $2700.