I am experimenting with developing an Ampleforth clone that, rather than tracking fiat through modifying supply, constantly decreases supply as price falls. In this way, a true deflationary asset is achieved.

Would anyone be interested in this?

Many thanks for letting us know. I have switched to the newer version and is working great.

It only leaves the Trezor firmware that we haven't checked.  You should be at version 1.5.2.  

But i would doubt that it is the problem since wallet.trezor.io works.

One thing i don't understand from your responses, is that you said that you were able to create new wallet files following my instructions, up to m'/44'/0'/2'.  If that is correct, than your Trezor does communicate with Electrum and your problem should be fixed.  

Do you have a laptop or iMac? How old is it and which version of macOS it runs?  

Did you try to install Electrum on another computer?

Does the website wallet.trezor.io works with your Trezor?

Don't mess around with your Trezor seed words - the problem is not with your Trezor.  There is no need to wipe it either.  

I would suggest to first ensure that you have the latest Electrum.dmg file from electrum.org

Next, open Finder, then select GO --> GO to Folder    
Enter   ~/.electrum    in the window that appears.  

Within the ./electrum directory, erase the config file.   Also move (or rename) all the wallets in the wallet sub-directory.  Don't worry, your private keys are in your Trezor, not on your computer.  The only thing you may loose by erasing an electrum wallet file that was created for a Trezor, are the labels you gave to each transactions. If you don't want to loose that info, just rename or move the file(s) somewhere else.

Start Electrum and create a new Standard wallet, with the Hardware wallet option.  If Electrum can communicate with your Trezor and create a new wallet at this step, your problem is solved and you should be good to go.  If not, you have a problem with your USB cable.  The cable supplied with the Trezor is notorious to be of bad quality.  Spend a couple of $$ and go buy a good one and that should fix your problem.

EDIT:  If the creation of the main account (m/44'/0'/0') worked, then you can proceed to create the second account of your Trezor (since it looks like you had setup two accounts on it).  The second one should have the derivation of m/44'/0'/1',  if you have a third account, m/44'/0'/2', etc.  They now have to be different files for each account, make sure you name them accordingly, when you create each new Electrum wallet file.

IF you have the seed, resetting both files could get your one wallet file back and produce the one HD walet that is needed instead of having two HD wallets under what I assume is the same seed (unless both have different seeds)?

Is your trezor wallet the latest version?
Do you have a backup of your wallet when there was just one wallet file (not the files that split). I don't know how they can split as they both use HD wallets so splitting the files would do nothing.

If not, and you have the seed, try restarting on a new paring if you haven't already.