Gnuplot 3D splot in tikz raw gnuplot (without pgfplots)

I have no idea how to steer splot from TikZ only. The following produces something reminiscent of the screen shot you seem to be looking for,

\documentclass[tikz,border=3.14mm]{standalone}
\begin{document}
\begin{tikzpicture}[scale=.5]
\foreach \Y in {-10,-9,...,10}
{\begin{scope}[shift={(0,0,\Y)}]
\draw[color=blue] plot[raw gnuplot,smooth] 
function{plot sin(x)*sin(\Y)};
\end{scope}}
\end{tikzpicture}
\end{document}

but obviously there are tons of things that could be improved, starting from an orthonormal projection.

What about knitr?

\documentclass{article}
\begin{document}
<<echo=F,dev="tikz",message=FALSE>>=
fsinsin <- function (x, y) {return (sin(x)*sin(y))}
x <- seq(-6, 6, length= 40)
y <- x
z <- outer(x, y, fsinsin)
library(lattice)
library(gridExtra)
trellis.par.set("axis.line", list(col=NA,lty=1,lwd=1))
wireframe(z, drape=T, shade=F, xlab="x", ylab="y",
col.regions=rainbow(150), aspect = c(1, .2), borders=F,
scales = list(arrows = FALSE),
colorkey=F)
@

\end{document}

What about using the gnuplottex package with the tikz output terminal (page 9, gnuplottex.pdf)?

Furthermore, if you have many pictures the tikz-package offers the possibility to externalize the pictures, see p. 11 gnuplottex.pdf.

Output:

Code:

\documentclass{article}
\usepackage{graphicx}
\usepackage{latexsym}
\usepackage{ifthen}
\usepackage{moreverb}
\usepackage{tikz}
\usepackage{gnuplot-lua-tikz}
\usepackage[miktex]{gnuplottex}
\begin{document}
    \begin{figure}%
            \centering%
            \begin{gnuplot}[terminal=tikz]
            set out "tex-gnuplottex-fig1.tex"
            set term lua tikz latex createstyle
            splot sin(x)*sin(y);
            \end{gnuplot}
        \caption{This is using the \texttt{tikz}-terminal. The function $f(x,y)=sin(x)*sin(y)$}%
        \label{pic:tikz}%
    \end{figure}%
\end{document}