Barge offer expression control and phase inversion options on the much smaller
VB-Jr. So I'd go with that... Or Wounded Paw make a blender in a wah enclosure, as do Morley.
If you want that exact discontinued pedal but with even more features (e.g. an impedance control so that it works well with fuzzes) then Barge do custom work - but if you're having trouble getting hold of them that's not good... Wounded Paw would also be able to do customised stuff though so try there.