Of course, anything can be meditated on, and it depends on your definition of "meditation". I currently only pray the Amidah for the purpose of initiating kavanah in my own path.
I have heard, perhaps from Scholem speculating or another scholar's work... perhaps even Aryeh Kaplan, that the Amidah was constructed in a manner similar to that of the methods involved in Merkabah/Hekhalot descent (basically meditation to gain admittance to the upper realms of the seven Heavens and/or halls of the Kingdom).
Does anyone have any stories about this or experience on such a matter?
Perhaps, because it can be seen as admitting yourself in, as opposed to being invited in (although, that is a gray area, in that how can someone force their way to the infinite or even a lesser part of the Eternal), it could be viewed as "evocation".
And if viewed as evocation, there must be somewhat similar methods incorporated by others.
The Solomonic style prayers, from what I've seen and of other evocation methods, are not as long as the Amidah; and Merkabah style work is known for it's use of many adjectives and lengthy prayers.
The only thing that immediately comes to mind are Gnostic works that deal with the Book of Enoch (1 Enoch) style ascent.