Check out endless pools or swim spas they are great i small spaces you will have to see if it can be inground or just an above ground one depending on where all the sewer lines and gas, water run through the space

Artful Pools Design and Consulting specializes in award winning pool designs in 2d and 3d. Small backyards are great to work with because design can make a big impact in a small area. Visit Houzz profile or www.artfulpools.com

HI -- Endless pool is a great idea or a long lap pool with the spa end .

You may want to post this question in the portion of the Houzz forums that addresses pools.

http://ths.gardenweb.com/forums/pools

A nice classic design would look nice with surroundings.

I love this backyard, skip the pool. If you must, contemplate something that looks like a pond with a dark bottom. This has a secret garden type feel, go with it. Make it look like you found a secret swimming hole or go with a formal small pool.

Here are some photos

Looks like a classic design would work the best? Need to see house area and focal point to make pool blend with house and great looking classic brick fence. Using brick accents and maybe a classic fountain tying in fence with a black interior to mirror image with great looking landscaping.

I would go with a dark bottom pool first and foremost. The rest will depend on your budget, tastes, and needs - for example, if you have children the second pool would not be appropriate. Consider additional options: hot tub/waterfall/seating area and large trees or a large trellis at the far end (where I would place hot tub for more privacy from apartment building) and granite slabs along the edge of pool.