\documentclass{scrartcl}
\csname @pushfilename\expandafter\endcsname
\expandafter\xdef\csname @currname\endcsname{scrsize11pt.clo}%
% Main loader, including \input or similar
\makeatletter
\InputIfFileExists{scrsize11pt.clo}{}{}
\makeatother
\csname @popfilename\endcsname
\begin{document}
aaa
\end{document}