There are more options:
Diysandbox.com Hydrogen WiFi shield and Platinum, which is a Arduino Mini with integrated WiFi.http://diysandbox.com/our-products/hydrogen-arduino-wifi-shieldhttp://diysandbox.com/our-products/platinum-arduino-mini-with-wifi
Also, the Bridge solution is not limited To use only the slow Wiznet W5100 based Ethernet Shield.
You can use either one of the W5200 based Ethernet shields, or if you'd like something small you can go with an embedded Ethenet module like the WIZ820io ($20 here in the US) with is also based on the W5200 chip.
Then as another port suggested you can get a pocket router that runs DD-Wrt, which is an embedded router Linux. For example the TP link TL WR703n is a very good choice as it can be USB powered.