fbl100

There are 4 different modules used mainly in 2.4GHz RC:
NFR24L01, CC2500, A7105, CYRF6936. For the most part, these are not compatible with each other.

Getting modules is easy. search on ebay or aliexpress and you'll find no shortage. All of the modules use an SPI interface. You can get modules with built in PA/LNA amplifiers to provide additional range.

To implement a new protocol, you need a logic analyzer, and to wire it to the transmitter or receiver (or sometimes both). This can be quite challenging as often there are no pads to solder to, and the chips are all QFN package which is a real pain to work with.

Then you need to capture initialization, binding, channel-selection, and data transmission and decode it to figure out what is going on.

It is not a trivial process. Some protocols are trivial. The Hubsan protocol only took a day. Some are hard. DSMX is still not fully known (though we have enough to implement it on the transmitter). Most fall in between and take a lot of work to analyze.

I have put transmit modules on my RaspberryPi which makes development a lot faster than doing it on the actual Tx, but you still need to go through all of the steps above.

I prefer the modules with a PA/LNB myself, though they are considerably more expensive. I keep thining of making a universal module, but need to keep the costdown.
Maybe I should look into taking 4 boards without PA, and attach them to a main board that contains the necessary digital switches and a PA. It would be easier than laying out hundreds of smt components and then soldering them in place by hand. Mymain purpose was to figure out how to keep the cost down. but you can get reference boards for ~$2 or less for all 4 chipsets, if I could get a board layout and the necessary switches, i might be able to make a universal module in the $20-$25 range. I'll give it some thought.

I'm sorry, but that entire post went right over my head.
I don't know what you mean by:
Universal multi hub
Muli Format Sensor Hub
MultiWii
DMS2

But from previous discussion, I am guessing you mean a module that would support lots of protocols and plug into the trainer port (like Hammer's module)? If that is the case, then you are right, I am not interested in working on such a thing even though I'm sure it would sell quite well.

I ordered a WL V922 which I believe shares the same protocol used by the fbl100. We'll see how it looks once it arrives.

correct. the V922 is not compatible with the V911. Nor is it compatible with the V202 (uses yet another hardware module). We're going to need a 'universal' module sooner or later to manage this terrible situation.