You mention something that is a HUGE problem point with current USB wheels that use DIN style connectors at the wheels… in that each manufacturer can wire them up differently which does not allow cross compatibility in the wire Since all of these are outside the USB Standard Spec… However ALL wired wheels run off of USB…
So this is general to all:
For most wheels right now they they are USB. they run off of the USB HID protocol for main functionality… most wheels do this directly with no drivers required if they have written their USB stack properly. This Functionality does NOT include screens but does include the ability for buttons, hat switches, and analog inputs… The USB stack for the wheels I produce is capable of 128x buttons 17x 16bit analog inputs, and 4x Hat switches (it took me quite a while to write this header though and have it be backward compatible with the windows Traditional HID interface)… In anywise that it a lot of items and we will probably never use all of them. This DOES NOT cover Screens or other visual inputs such as LEDs which are usually run through a USB-Serial connection.
This USB serial connection is also sent over the same lines as the USB HID hence why USB only needs the 4 main wires (USB 3.0 uses more wires due to the split bus to gain SuperSpeed).
this 4 wire USB2.0 set-up is generally common and I can guarantee that most every manufacturer is fully capable of this setup… which is why having USB pass through the wheel base is actually a very good thing.
When it comes to wireless wheels and conversion to line powered USB this gets much more difficult as generally speaking and in the Case of the SimuCUBE the wireless aspects are provided to the Manufacturer by selling a proprietary board to them with whatever functionality they include. (Simucube Wireless Module) This is integrated into the design of the wheel and as such controls all the data so there are no USB Data lines present. These could benefit from Line Power as it would eliminate all of the battery issues and provide a much more constant power supply.
There are limitations with USB, the biggest being the 500ma “max” Some hubs can provide a bit more amperage but if they want to be within spec it isn’t supposed to exceed 500ma… Having a Powered Hub (if that hub is designed correctly) will provide 500ma to each port in the Hub. If the hub is unpowered it splits the base 500ma between all the ports on the hub (significantly limiting power availability)
Screens and LEDs can be Power HOGS and eat up that 500ma availability very quickly and the way to get around this is to not use the USB power bus and use a second power bus more capable than 500ma… This however would require a power line OUTSIDE of the USB (if your desire is to stay within USB spec. this becomes more complex in ways but fundamentally sound…
Basically though converting a wheel that is currently on USB to any OTHER sort of USB connection is not a big deal… Converting a Proprietary system such as the SimuCube Wireless to USB (that is a problem)
And about SimHub… There is a danger for a company to use open source code (not only with licensing) but the fact that in many cases that code is really only being further developed by one or two people… When/if those people get tired of dealing with the code, development dies and since the company has no real control over it then they have issues with longevity… This means that if SimHub decides to stop doing what they are doing then all those wheels and displays that use SimHub will be stagnated and or stop working depending on if windows would change things afterwords, This could be a support NIGHTMARE for a company. I am honestly surprised so many companies have adopted the use of SimHub but it is by far the easiest manner to place lights and displays in wheels… But if you don’t want to or can’t use SimHub for the inherent issues with using a third party system within a first party product then it is not so easy…
This is most likely why you are not seeing a SimuCUBE branded wheel with LED’s or a Display… Well that AND it cannot actually be wireless until the SimuCUBE Wireless module can support serial data transfer and the power requirements of the LEDs/Screen. Licensing issues come into play here as It is probable that by integrating SimHub into the wireless module by the GPL they would be REQUIRED to release the firmware code for the entirety of the wireless transmitter which would allow anyone to produce a SC Wireless Transmitter. (Which of course Granite does not want to do as they want to sell the units to the wheel manufacturers and not have them be able to produce their own)