I'm tired of qmake.
So don't use it.
Other example: I can't compile any qt project from my MacOSX to a Windows executable. qmake doesn't supports cross-compiling? it really sux
I don't understand that. You want to compile Qt project on MacOS X into Windows exe? So what qmake has to do with it? Compile it? I don't have any problems making makefiles from .pro file, on Windows I make MSVC makefile and on linux I make suitable makefile for my linux. Maybe take a look into Qt Assistant and type "qmake" in it.
I want qmake installs a .exe file when i do a make install on windows and qmake installs a .app directory when i do a make install on MacOSX! Also, I want qmake installs a .bin file and gives execution rights to it when i do a make install on linux, but I think qmake will never be able to do
Maybe use a suggestions page on Qt Software web page, if you have any suggestions.

And finally, how can we help you? If you dont like qmake or Qt at all, you have to look for suitable command for your OS, which do such a thing as "remove". Try maybe "rm -rf /your_qt_dir" or something like "rmdir". I think Google can help you.