A quick search turned up Fastmac replacement batteries which claim to

...replace the computer’s original battery with a larger capacity and longer lasting advanced power cell battery that utilizes TruePower technology. With up to 68% more capacity...

Bookarc looks great, but closing the lid means thermal problems. It's not meant to be used that way, and under full load, this probably will lead to noise and overheating. I was planning to buy a stand (since I use my MacBook Pro with external monitor and keyboard), but inadequate cooling stops me, however keeping it open all the time accumulates dust.

Here is my "Reverse V" method

1. Connect all cables (video) and close the lid.
2. Wake from external mouse/keyboard. This will force using only the external display.
3. Open the lid to about 20-40 degrees. Internal display will remain off. The Macbook will be in a "V" like shape.
4. Put it on the desktop in reversed "V" form on something soft. I recommend old polyurethane mouse pad or shaped polystyrene.

    /\\
   /  \\     - MacBook
  /    \\
===========  - mat/soft mousepad

Pros

• Perfect cooling. Warm air gets up, there are no obstructions to the vents and all parts are exposed to colder air.
• Cooler means less fan noise under load.
• Takes less space than fully opened notebook.
• Better bluetooth/wifi reception because lid is not fully closed (compared to fully closed one).
• Less dust accumulation.

Cons

• You cannot use your internal IR receiver.
• Some people will not be comfortable to run their HDDs from this position (10-20 degrees vertical inclination). I think it's perfectly safe.. and I have trustworthy backup system.
• If computer sleeps, you should do the steps from 2-4 again or the internal display will be on.
• Looks kinda strange compared to the great looking vertical stands available.