I would like to be able to combine font changing commands using unicode-math in a math environment. For instance, I define a symbol as being in an upright font, but I want a bold version of that upright symbol. I was thinking that \symbf{\symup{V}} would work, but it does not. There are the commands \symbfup and others to specify both font faces. How can I accomplish combining them? The actual use case is shown in the MWE below:
\documentclass{article}
\usepackage{unicode-math}
\setmathfont{TeX Gyre Pagella Math}
\newcommand*{\velocity}{\symup{V}}
\newcommand*{\vectorsym}[1]{\symbf{#1}}
\begin{document}
$\velocity \quad \vectorsym{\velocity} \quad \symbfup{V}$
\end{document}

\mathbf{\mathsf{X}}would give you a bold sans X. Maybe if I get some time to look at the code again over the Christmas break… – Will Robertson Dec 14 '15 at 02:31