Here's a bizarre idea - How about switching LaTeX's interpretation of \section and \paragraph?! That way, you "upgrade" a paragraph to tocdepth level 1, while "downgrading" a section to tocdepth level 5. A little reconfiguring of the traditional formatting is necessary of all section-dependent counters (including section and subsection) though. The original definitions of \section and \paragraph were taken from the article document class:
\documentclass{article}
\usepackage{titletoc}% http://ctan.org/pkg/titletoc
\usepackage{lipsum}% http://ctan.org/pkg/lipsum
\makeatletter
\renewcommand\section{\@startsection {paragraph}{1}{\z@}% Sections are paragraphs
{-3.5ex \@plus -1ex \@minus -.2ex}%
{2.3ex \@plus.2ex}%
{\normalfont\Large\bfseries}}
\renewcommand\paragraph{\@startsection{section}{5}{\z@}% Paragraphs are sections
{3.25ex \@plus1ex \@minus.2ex}%
{-1em}%
{\normalfont\normalsize\bfseries}}
\makeatother
\renewcommand{\theparagraph}{\arabic{paragraph}}% Section numbering
\renewcommand{\thesubsection}{\theparagraph.\arabic{subsection}}% Subsection numbering
\begin{document}
\setcounter{tocdepth}{1}% Show only "sections"
\titlecontents*{section}[1.8pc]% "Section" formatting
{\small}
{\thecontentslabel. }
{}
{, \thecontentspage}
[---][.]
\tableofcontents
\section{Section 1}
\subsection{Subsection 1}
\paragraph{Bla1} \lipsum[1]
\paragraph{Bla2} \lipsum[2]
\paragraph{Bla3} \lipsum[3]
\paragraph{Bla4} \lipsum[4]
\paragraph{Bla5} \lipsum[5]
\paragraph{Bla6} \lipsum[6]
\end{document}
To obtain the required formatting, only tocdepth level 1 items are shown (the new paragraph) using \titlecontents* from the titletoc package.

The table of contents shows the paragraph name, following by a comma ,, the page number and a dash ---. The last entry ends with a period .. This can be modified by changing the paramaters of \titlecontents*.
\setcounter{tocdepth}{5}to your document preamble. I'm more-or-less referring to this entry in the UK TeX FAQ. – Werner Oct 03 '11 at 21:35