How to remove blogspot's top frame ?

Don't know how long this solution would work.

If you look at HTML source of the page it has the following style that is getting inserted into the web page:
#navbar-iframe { display:block }

So, all you have to do is to add into your blog's template something like this:

#navbar-iframe{
height:0px;
visibility:hidden;
display: none !important;
}

Good Luck!