"Find On Page" Search Plugin

No need for a WP plugin really. Will you be usurping the standard WP search box or this an additional input field?

You could probably just you this jQuery plugin:

https://johannburkard.de/blog/programming/javascript/highlight-javascript-text-higlighting-jquery-plugin.html

and call something like this in a docready:

$('input').keyup(function(){
	$('*').removeHighlight();
	$('*').highlight($(this).val(););
});

I have NOT tested this.

Any joy with this OP? I have a similiar issue…