The MnSymbol fonts have corners that can be used as you'd like
\documentclass{article}
\DeclareFontFamily{U}{MnSymbolE}{}
\DeclareFontShape{U}{MnSymbolE}{m}{n}{
<-6> MnSymbolE5
<6-7> MnSymbolE6
<7-8> MnSymbolE7
<8-9> MnSymbolE8
<9-10> MnSymbolE9
<10-12> MnSymbolE10
<12-> MnSymbolE12}{}
\newcommand{\mnquote}[1]{\usefont{U}{MnSymbolE}{m}{n}\char#1\relax}
\newcommand{\quinelquote}{\raisebox{.1ex}{\rlap{\mnquote{'036}}\kern.2em}}
\newcommand{\quinerquote}{\/\raisebox{.1ex}{\kern.2em\llap{\mnquote{'043}}}}
\let\nipponlquote\quinelquote
\newcommand{\nipponrquote}{\/\raisebox{-.1ex}{\kern.2em\llap{\mnquote{'055}}}}
\begin{document}
\quinelquote Bcdef\quinerquote
\nipponlquote Bbcdefg\nipponrquote
\nipponlquote Bbcdef\nipponrquote
\end{document}
However the problem with \nipponrquote is with descenders: this quotation system works with Japanese because its glyphs don't have descenders. The compiled example shows this weakness with the latin alphabet. However the same problem arises when the letter adjacent to the closing "Quine quote" has no ascender.

hyperref-boxes (around links). (3) It seems to lead to some font errors in the pdf-file (I didn't spend much time trying to fix this). In brief, too much of a trial-and-error curve for me right now. That said, if you are familiar with those issues, I'll be all ears. – Lover of Structure Jul 1 '12 at 7:46