Wow, I gotta say, I never thought I would see anyone asking to do this. All the keyboard options for texting was one of the big draws for me. I was way too slow on the old # pads.
Me also...If I try two thumbs in portrait I fail, but one and I can type super fast. I am also getting darn fast on landscape mode.
To the OP...you just need to practice and you will get much much better. "The quick brown fox jumps over the lazy dog" I believe....somebody correct me if I am wrong. For those thinking I am crazy, this phrase should contain all letters of the alphabet.