This is stupid. Still, I've got a solution, based on egreg's:
\newcommand\stupid[1]{%
\vbox{%
\hsize=4.5in
\parindent=0pt
\leftskip=0pt plus.5fil
\rightskip=0pt plus-0.5fil
\parfillskip=0pt plus1fil
\emergencystretch=1in
\parshape6
0.00in 4.50in
0.25in 4.00in
0.50in 3.50in
0.75in 3.00in
1.00in 2.50in
1.25in 2.00in
\huge
\bfseries
\strut
#1%
}%
}
The \parshape
specifies what to do for the first 6 lines by giving pairs of numbers. The first in the pair is the indentation and the second is the line length. The settings of \leftskip
, \rightskip
, and \parfillskip
come from TeX by Topic and are used to center the last line.