What options are there for cloud based FFMPEG processing?
Actually you can use Cloudinary for video processing as well.

Cloudinary's API allows you to build manipulation URLs and embed a HTML5 video player with all the video sources and settings.

Original videos are stored in the cloud and you can then dynamically create multiple resized, cropped and manipulated videos on-the-fly and deliver them via dynamic URLs or use code to either add video tags or build the URLs.

For example if  you want to resize a video to a width of 150 pixels and a height of 100 pixels, the dynamic URL will look like this:

 http://res.cloudinary.com/demo/video/upload/w_150,h_100/dog.mp4


You can also rotate the video by any arbitrary angle in degrees with the angle parameter (a in URLs). For example rotating a video by 90 degrees:

 http://res.cloudinary.com/demo/video/upload/a_90/dog.mp4


If you want to add text overlays, use the text: property of the overlay parameter ( l_text: in URLs), followed by the font name and size (separated with an underscore), a colon, and then the text string to display. 
For example, to overlay the text string "Sample Video" in the Arial font with a size of 40 pixels:

l_text:arial_40:Sample Video.