The notion of a taller-than-skyscraper, so called "megatsunami" is not new - with the often-reported 524m (1720 feet) high Lituya Bay tsunami of 1958 is sometimes referred as such (despite the wave not reaching that high). In many movies (and some documentaries), there are massive tsunami depicted. Some of these movies depict tsunami taller than skyscrapers (such as in Deep Impact and Haeundae). There is also evidence of massive tsunami occurring in different places around the world in the past.
We have seen the reality of devastating tsunami in and around the Indian Ocean in 2004 and Japan in 2011 for example. These, while not being 100's metres high, are still catastrophic.
How a tsunami forms and how it travels is well documented (thus is not the subject of this question), nor is this asking about the inland reach of such a disaster, they are answered in the related questions Is a mega tsunami that will destroy America inevitable?, Is Atlanta too far inland and too far above sea level to be affected by the comet in “Deep Impact”? and Why does every tsunami travel differently?. But rather, the maximum height possible for a tsunami from any cause.
Is there a theoretical upper limit for the maximum height of a tsunami?