‘LaTeX’ logo with kerning issue and not scaling properly

Without digging into the code, it seems that the \LaTeX logo chooses a one step smaller font size for the ‘A’, and thus when encountering \tiny there is no smaller step available, destroying the proportions. I think this is as close to finding a bug in the (La)TeX system as I will ever get ;). Small caps is just the logical choice for that A, it fits in beautifully, but they might not be available for a different typeface.

I defined a new command \myLaTeX which uses the small caps provided by Linux Libertine for the ‘A’ and has the proper kerning between the letters. The spacing is font size dependent using em for horizontal and ex for vertical spacing. As the screenshot shows, it behaves nicely with different font sizes:

\documentclass{article}
\usepackage{libertine}
\DeclareRobustCommand\myLaTeX{%
    L\kern-.3em%
    \raisebox{.4ex}{\scshape a}\kern-.13em%
    T\kern-.2em%
    \raisebox{-.5ex}{E}\kern-.13em%
    X%
}

\begin{document}
\centering
{\tiny\LaTeX\ \myLaTeX}

\LaTeX\ \myLaTeX

{\Huge\LaTeX\ \myLaTeX}
\end{document}

Alternatively, the package metalogo can adjust the TeX logos, which is often needed, for many fonts. It would be possible to fix the kerning and the weight of the ‘A’, but I'm not sure about the scaling behavior.

With metalogo:

\documentclass{article}
\usepackage{libertine}

% keep the original for reference
\usepackage{letltxmacro,xpatch}
\LetLtxMacro\oldLaTeX\LaTeX
\LetLtxMacro\oldTeX\TeX
\xpatchcmd{\oldLaTeX}{\TeX}{\oldTeX}{}{\ddt}

\usepackage{metalogo}

\setLaTeXa{\scshape a}
\setlogokern{La}{-.3em}
\setlogokern{aT}{-.1em}
\setlogokern{Te}{-.08em}
\setlogokern{eX}{-.1em}
\setlogodrop{0.33ex}

\begin{document}

{\fontfamily{cmr}\selectfont\oldLaTeX}

\LaTeX

{\tiny\LaTeX}

\end{document}