As in the title, I'd like to be able to select whether TeXShop uses biber or BibTeX in the document rather than using the command line or changing the default in the TeXShop preferences.
For TeX engines this is easy; i.e. you can put the following somewhere near the top of your TeX file
% !TEX TS-program = pdflatex
to tell TeXShop to compile with pdflatex, regardless of the default in the preferences. Does such a directive exist for bibliography passers? I want to be able to hit ⇧+⌘+B for this. Latexmk provides the ability to do this, but I want to do compilations manually.
Final note
The solution involved a shell script. I've made this available on GitHub, so please feel free to use and improve it.

% !TEX...line meant for TeXShop? – qubyte Dec 16 '11 at 16:26#!/bin/shby#!/usr/bin/env shfor the sake of portability and user-friendlyness. – Xavier Jul 27 '13 at 23:47% !BIB TS-program = _____), then TeXShop pops up an error message claiming that the TexShopBib.sh file itself does not exist. @qubyte: Any fix for this? – jvriesem Jun 24 '15 at 17:27/usr/texbinwhich puts the script in TeX Live's main installation tree.... – cfr Jun 26 '15 at 13:01