Does it have to be round? I have a frame-like thing similar to that, currently holding an embroidery project my Mother never finished. You can have it if you want it.

Oh, here: it is this,http://www.scottishfibres.co.uk/acatalog/Embstand4.jpg but much less fancy (basically dowel rods) and about 15-18-ish inches across. I can measure it later if it's what you're looking for.