Apenas encontrei este que suporta os formatos abaixo:
http://www.smartftp.com/client/addons/sourcepreview
ActionScript (.as, .mx)
ASP (.asp)
ASPX (.aspx)
AutoIt (.au3)
Bash (.sh, .bsh)
Batch (.bat, .cmd)
Caml (.ml, .mli, .sml, .thy)
C (.c)
C++ (.cpp, .cxx, ,.cc, .h, .hxx, .rgs)
C# (.cs)
CSS (.css)
Diff (.diff, .patch)
Fortran (.f, .for, .f90, .f95, .f2k)
Ini (.ini, .inf, .reg, .url)
Inno Setup (.iss)
Java (.java)
JavaScript (.js)
Lisp (.lsp, .lisp)
Makefile (.mak)
Matlab (.m)
NFO (.nfo)
NSIS (.nsi, .nsh)
Pascal (.pas, .inc)
Perl (.pl, .pm, .plx)
PHP (.php, .php3, .phtml)
Python (.py, .pyw)
Resource (.rc)
Smalltalk (.st)
TeX (.tex)
SQL (.sql)
VB (.vb)
VBScript (.vbs)
XML (.xml, .xsd, .xsml, xsl, .kml)