Considering that "converting" consists of nothing more than making the proper wiring, I doubt that these can be different from the generic Neutrik adapters. There's really nothing that can possibly be specially designed.
Unfortunately it is not so easy. Adapters differ on what is done with the unused XLR pin. Some float it, others shortcircuit it to pin 1, one brand uses a resistor to connect it to pin1.
IMO you should consider each case independently - male and female adapters need different connections. The topology of your balanced cables will also influence it.
You will probably need custom adapters to optimize the system - I suggest buying a few Neutrik connectors and a soldering iron, an ohmmeter and some resistors! My adapters were built this way, using small bits of Nordost solid core .8mm cable - it was what was available in my tool box!
Unfortunately it is not so easy. Adapters differ on what is done with the unused XLR pin. Some float it, others shortcircuit it to pin 1, one brand uses a resistor to connect it to pin1.
Yes, just summarized before adding two more lines that I feel are relevant. Most people do not realize that there is no universal formula to use a specific XLR cable in single ended mode.