However …..

The following ten-letter words with this feature all appear in W2: PEPPERROOT, PEPPERWORT, PERPETUITY, PEWTERWORT, PIROUETTER, PREREQUIRE, PRETORTURE, PROPRIETOR, REPERTOIRE, REPETITORY, TETTERWORT. These words have also been suggested: PROPRIETORY, PROTEROTYPE, RUPTUREWORT, PITUITOTROPE, UROPYOURETER. Chris Cole (Wordplay) gives TEETERTOTTER, although MWCD10 spells the word with a hyphen. A person who rides a teetertotter would be a TEETERTOTTERER [Stuart Kidd]. A reader of this page suggests POWERTRIPPER, although this word seems not to be in dictionaries. EUROPE and PERU can be typed using only the top row of keys; Europe is the only continent that can be typed using a single row of letters.

Interesting!

EDIT: Sorry, I didn’t even try to come up with words. I know some folks have a thesuarus and many other tools right at their fingertips, and I only have the ancient little brain and an old and tattered dictionary… oh, and the MSN encyclopedia. There may be more but this computer is still a new-fangled contraption to me…

“Common words of ten letters that can be spelled solely with the top line of letters on a QWERTY keyboard include perpetuity, proprietor, repertoire and, fittingly, typewriter (though this may have been a deliberate goal driving the design of the QWERTY layout[citation needed]). There are at least two eleven-letter words, both rare: proterotype and rupturewort.”

priority property properer requite rewrite pewter (using them more than once)