Learn English – How to eat your eggs

I apologize in advance for not being able to provide a more well-documented answer, or even a whole answer, but I did find this.

From: Eureka Encyclopedia

Boy (Broad boy; Buff boy; Business boy; Call boy; Career boy; Come-on boy; Fag boy; Party boy; Pratt boy) Male prostitute.

it also lists

Rent Boy

and

Baggage Boy

You could try it, but it would be non-standard and likely misconstrued.

The order

verb => object => out

as in

shout Karen out

brings up all kinds of extreme associations, since out used in that way usually means to do something completely.

I kicked Jim out.

We threw them out.

Rachel found Jim out, finally. He'd been cheating on her for weeks.

You've got beer? Bust it out!

You two fight it out. I want nothing to do with this.

I thought I had the right word, but in the end I crossed it out.

This is out used in the completive sense of "at or to an end" (NOAD), so I would suggest to you that "to shout someone out" may not be the best alteration of the more familiar "shout out to someone" trope.