[Texasrocker]

You may try contacting Freeman-Tuell Spkr Co in Dallas. They dont have a website, but google-search their name will find their phone number online if you wish. They can still service vintage field-coil type spkrs, "if" they have a paper-cone that retrofits.They do Great Work!! F-T Spkr has been in business in Dallas since the 1930s,.. Reasonable prices too.

Another alternative, is to use a 8" full-range pm type spkr such as the musak type ( search rauland type 8" spkrs on ebay), will usually turnup a good sub to use with a appropriate size wirewound resistor to sub for the old field-coil.
To mount the spkr without changing the orig cabinets front appearance, cut a new spkr "baffleboard" to fit inside the cabinet, and use the orig decorative mounting studs to hold it in place. The pm type sub spkr can be mounted to the baffle-board without disturbing the orig cab, and can be removed to put the radio back to orig in the future if you can find a orig spkr. Make a "template" from thin cardboard so concessions can be made for proper-spacing a retrofitted spkr. In Philcos, a retrofitted spkr baffle has to clear the tuning assembly when orig chassis is installed, and spkr will be mounted abit higher in the cabinet. A bit of crafty-engineering with a sabre-saw,small drill & bits,to build a new small spkr baffle-board, will get you listening to your radio sooner than later! Just takes abit of good measuring, and a replacement spkr can be retrofitted indeed without any damage to your orig cabinet at all! Enjoy your vintage Philco!