According to a film my wife saw in her philosophy class, Bertrand Russell received a letter from a woman who proclaimed herself a solipsist.
She went on to say that she was surprised that there weren’t more solipsists.
Besides myself (although I consider myself only a part-time solipsist 
), noted SF writer Robert A. Heinlein probably was one – at least he wrote several solipsist stories and even introduced the philosophy of “pantheistic multiperson solipsism” in his magnum opus, The Number of the Beast.
Possibly as a satire of this, Iain M. Banks features a band of solipsists in his Against A Dark Background. Here’s a slightly abridged dialogue between the book’s heroine, Lady Sharrow and the solipsist leader, Elson Roa:
“But if you’re God… why do you need the others?”
…he shrugged. “My apparences? They are the sign that my will is not yet strong enough to support my existence without extraneous help.”
…”What about the others? Do they – the apparences – call themselves God, too?”
“Apparently… um, apart from one, who’s an atheist.”
“Ah-ha”, she said, nodding slowly. “And what does this person call himself?”
“‘Me.'”
“… uh-huh.”
