pdftosrc and pdftoepdf are part of pdftex, and are included in tetex-src-3.0.tar.gz but do not get installed by the ebuild. From my log of emerging 3.0-r2, I see that the binaries are successfully built, just do not get installed. During the build the binaries are compiled into: .../tetex-3.0-r2/work/tetex-src-3.0/texk/web2c/ There may be other binaries there, too.
Argh. I misread part of the log. pdftoepdf.o only ends up as part of libpdf.a, not an executable of its own. The bug remains valid however wrt pdftosrc.
I have added the pdftosrc binary and man page to the tetex-3.0_p1-r2 ebuild. Thanks for reporting (and sorry it has taken so long)!