I'm under the impression that this is against CloudFlare's ToS, otherwise I'd probably be doing it myself.
See section 2.8 "Limitation on Serving Non-HTML Content." of their subscriber agreement:
use of the Services for serving video or a disproportionate percentage of pictures, audio files, or other non-HTML content is prohibited, unless purchased separately as part of a Paid Service or expressly allowed under our Supplemental Terms for a specific Service.
Last I checked, SSH is non-html content. I even opened a support ticket with their support, specifically asking about SSH and other traffic and this is what I received: So if no matter what service you use, Once you breach this rule it will be applied.
EDIT: Looks like the CloudFlare CTO has clarified things below that this usage does not in fact violate the ToS.
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