You now can use this in templates:
{::font size="xs"}Tim is a very tiny genius{:/font}
{::font size="s"}Tim is a tiny genius{:/font}
{::font size="m"}Tim is a medium genius{:/font}
{::font size="l"}Tim is a big genius{:/font}
{::font size="xl"}Tim is a very big genius{:/font}
which gives this as a result :