Looks like we have three contenders - the HG08 from CNC4YOU, the ZP5A from Zapp and the Uniport from DIYCNC. Although it's the most expensive, the Uniport is currently my favourite from these as it includes a charge pump and two relays, plus opto isolation on the inputs. COmes in at £40 posted, so not too bad.

Anyone have any experience of using one of these in anger?