It's not really a clone if it's a different chip, more like a spinoff.. I needed more ram when using the ENC28J60 ethernet chips. The TCP stack is in ram, rather than in the chip, so it takes most of the ram. So I used the Teensy++ 2.0, really cheap, uses the Arduino IDE just like I'm used to, and has like 8k of ram. Though nowadays, I'd use the Teensy 3.0, it's got 16k of ram and is cheap as dirt.