Here's the factory solution to the armrest issue, and it looks like a good one, as it looks to come pretty far foward for comfort.

http://i81.photobucket.com/albums/j211/turbo-paul/ScionLV/xDArmrest.jpg
• Provides a comfortable place for driver or passenger to
rest their arm.
• Made from injection molded ABS plastic that matches the
factory interior.
• Covered in a soft yet durable padded fabric for comfort
and durability, and the fabric matches the factory interior.
• Rotates up and down for easy access to the parking
brake and so it won’t be in the way when not it’s not in
use.
• Specifically developed through Toyota to meet or exceed
all OEM Quality Control requirements.
• Made of the highest quality materials.
• Easy to install. No drilling required.
http://i81.photobucket.com/albums/j211/turbo-paul/ScionLV/xDArmrest2.jpg


http://i81.photobucket.com/albums/j211/turbo-paul/rock.gif

already been posted...thanks for the part number though!