Does the speaker really need reconing, or does it just have a few holes or rips?
I have successfully patched speakers using tea bag paper and flexible glue. You can buy a special "service cement" made by GC but many people report success using flexible glue from a craft store. Some people even use coffee filter paper. Your TV's audio section is not a high-fidelity system; a patched speaker will sound just like the original.
Tea bag paper is so light that it will blend in pretty well with the speaker material. If that doesn't satisfy you, you could darken it with a magic marker but I would not paint the cone.
Just an idea . . .
Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html