As 
Taurian said in the OP, "This would be a great addon. The ability to communicate with Exit Games: Photon Cloud Service."
But we had to wait six months before ExitGames came out with their JavaScript Cloud SDK. And then you had to wait while I converted the alpha version of my PhotonPlayer plugin for the Photon Server (see my post of 7 July 2012) to a PhotonClient behavior for the Photon Cloud. And I had to wait till the busy Photon team found time to join in on the development.
But I decided I couldn?t wait, so I?ve pressed ahead on my own, picking my way through the rather sparse internal documentation of the Photon Cloud JavaScript SDK, to come up with a Construct 2 demo of my PhotonClient behaviour for the Photon Cloud.
This is what you can expect to see when you run the demo and you?re the third to join in with two players already playing on two other PCs (I?ve not tested it on other devices):
<img src="http://www.millercrawford.com/images-offsite/construct2/photonclient-workout.png" border="0">
So, to get my Workout demo up and running:
1) Register with ExitGames for a Photon Cloud Account on their ?Forever Free Plan?, which gets you an app with a maximum of 20 CCU. You?ll be given an Application ID that you?ll need in Step 4. (It?s a generated identifier for your Photon Cloud application, used when an app client connects. It separates the users of your app from users of other Cloud apps.)
2) You now need access to a HTTP web server (if you haven't got access to a remote server, you can use localhost for an in-house demo). Set up a folder on that web server from which to serve your workout demo ? I?ll call it ?photonclient.workout? in the following steps.
3) Download the Workout demo files from my Dropbox account: https://dl.dropbox.com/u/54915877/photon.workout.zip
4) Into your photonclient.workout folder, copy all the files from the Dropbox download, preserving the subfolders (css, images, media, photon).
5) Load into a text editor the cloud-app-info-template.js file that?s in the photonclient.workout folder.
6) Save that file back into the same folder renamed as cloud-app-info.js.
7) Edit it to change the MasterAddress string value to your nearest Photon Cloud Master Server ? you can find a list of them at http://doc.exitgames.com/photon-cloud/Regions/#cat-reference. You'll need to replace 'port' (following the colon) with '9090' (just the four digits, not the quotes).
8) Change the AppId string value to the Application ID you were given in Step 1.
9) Open a browser (Firefox/Chrome/Safari/IE10) and access the photonclient.workout address where you copied my Workout demo files, and which now also contains your own edited cloud-app-info.js file.
10) Type in your 3 character nickname and click the 'Join' button.
11) Text a friend and get them to do the same. (If you haven?t got a friend, you can go to another computer yourself and do the same. If you haven?t got another computer, you can open a second browser and do the same.)
12) Move your player and your friend/you should see it move in their/your other computer/browser. You're multiplaying with Construct 2!
13) Try banging into one of the other players.
OK, so now you?re keen to load my PhotonClient behavior into Construct 2 and try developing a multiplayer game for yourself. I?m afraid you?ll have to wait (yes, again!) for a couple of days while I complete the documentation. In the meantime, here?s a tantalising excerpt from the event sheet for my workout demo (just to prove it really has been made in Construct 2):
<img src="http://www.millercrawford.com/images-offsite/construct2/photonclient-workout-event_sheet.png" border="0">