Every year Ilford invites orders to manufacture film in a number of non-standard or obsolete sheet and roll film sizes. It's known as the ULF film order, but it isn't restricted to ultra-large format film. Among the various sheet film sizes, one of the notable items last year was the provision of HP5 Plus in 50ft lengths of 46mm, the size of 127 format; evidently last year's run had sufficient demand for Ilford to offer this size again.
The deadline for orders this year is Friday 27th June. For more information see Ilford's website: http://www.ilfordphoto.com/products/page.asp?n=137