The new Andaz Tokyo? Guest rooms start at the 47th floor and should have pretty spectacular city or bay views. It's a five minute cab ride from Hamamatsucho where you can get the monorail direct to Haneda's international terminal in ~15 minutes.

The Conrad Tokyo is also near the monorail station; but the city views are poor - the bay/garden view is rather good though.

If you're prepared to add an extra 10 or so minutes to your journey, that opens up the cluster of luxury hotels from Hibiya through to Nihonbashi: Peninsula, Shangri-La, Mandarin Oriental are all high-rise. The Four Seasons is also there but it's on the lower floors of the building.

Going west, you can find the Ritz Carlton at Tokyo Midtown in Roppongi/Akasaka, which is also a super-high-rise with spectacular views. The Grand Hyatt higher floors are OK, but not comparable to the Ritz Carlton in the view department; it is half a rung down on the luxury scale also. The ANA Intercontinental at ARK Hills is reasonably tall (30 stories?), but I've always had obstructed views as its surrounded by equally tall buildings; it's also a whole rung down on the luxury scale from the Ritz/Pen/Shang/Mandarin/etc.

I haven't stayed at the Andaz but I'd guess it's a peer of the Conrad/Grand Hyatt in the luxury stakes. These are all very good hotels.