Two 100mm 1:3.5 Cosina macros (1:2) currently listed on ebay.uk. The one closing later would seem to be NIB with the matched 1:1 lens. Both sellers apparently willing to ship outside UK.
These should be the pretty highly regarded "plastic fantastic" / bargain macros :
Cosina 100mm F1:3,5 MC Makro Lens Reviews - Pentax Third-Party Lens Review Database and
Cosina AF 100mm f/3.5 macro (Pentax) - Review / Lab Test Report
I have this as the MF version, branded Promaster: ABSFAB for US$ 82 (NIB with the 1:1 adapter).