I managed to create a .app/dmg of Bitmessage after I got it to successfully install on my Mac. So far I've had a couple of people report that it works, but feel free to test it out.

Credit: medoix for technical assistance

Ok, here's the link: https://mega.co.nz/#!PJFB3bjQ!N_4SGGxo5gcr65ubabowd1dZPTpIOdf_Pb2j7hBO9js