Yes. A.O. Spare used this technique and also amplified the emotional charge by directing sustained sexual intensity into the image of the desired circumstances. As you said, the "image" is refined down to an elementally simple sigil the way you describe - using the alphabet. One can also invent an alphabet over time with certain elemental shapes representing specific qualities and conditions to be used over and over again in new combinations if desired.
My wife and I have practiced this sigil/imaging work with similar tantric yoga techniques for some time now. We've experimented a bit with a technique called "eroto-comatose lucidity".
http://www.sacred-texts.com/oto/lib451.htm Regardless of the way you generate intensity, the trick is to train yourself to forget the sigil/image/visualization completely in that blank/null state that arrives at the end of the exercise.
The sexual techniques are extraordinarily potent, which I suspect is the main reason why organized religions have endorsed oppressive sexual taboos involving moral shame, guilt and fearful (false) associations with filth and evil, merely to prevent practitioners from using their innate human sexual/creative powers as nature clearly intends.
After working with these techniques, we've had manifestations in as short a time as a few days. Of course, larger manifestations take longer to come about, but our experience has been that not only have life-altering manifestations of new circumstances happened on schedule, but have always brought with them even better conditions than we had originally visualized.
These techniques are very effective. They've also been good for our marriage partnership, enhancing our level of intimacy and commitment. (Great fun too!)
Love helps.
:-)
J