Randy,
Most of the major suppliers (Dadant, Mann Lake, Kelley, etc.) sell small cell (4.9mm) wax foundation. I you haven't wired frames and embedded foundation before I could show you how. People have presented on this at past meetings I believe too.
Mann Lake sells PF100, PF105, PF120, and PF125 plastic frames that are 4.9 mm. Perhaps Rich knows of someone else who sells plastic foundation that measures 4.9mm?
If you start with bees from 5.4mm comb the bees usually draw out Mann Lake frames pretty well, though sometimes they can be a little reluctant to draw it out compared to wax. With wax foundation the larger bees will often re-work it to somewhere around 5.1-5.2 mm at first, but as the bees get smaller they more reliably draw it out. It can be a bit frustrating at first, but if you want to make small bees it can be done. Drawn small cell comb will make them small quicker, but it's hard to buy. There are a few suppliers of small cell packages and nucs too. Of course, with respect to nucs, you have to have standard equipment or you run into issues there too; there aren't many people supplying top bar nucs, and top bar hives aren't standardized like Langs are.
Regards,
Joe