The nature of sound shortening is often, due to the environment that spawns such changes, rather 'casual' and colloquial.
Much like how 様 and さん have relatively different levels of 'politeness' so do お疲れさま and お疲れさん.
(Speaking merely from personal experience, I have only used お疲れさん among friends and casual acquaintances in informal situations. Among equal colleagues, in working / formal environments I have never heard such abbreviation of お疲れ様)
This will likely be the main reason you will not have heard it said by and individual of lower status, to one higher status. (i.e. it would be impolite to do so.)
(As a side note, another reason will be due to a long standing societal norm that 労い／慰労 'thank or praise for ones efforts / work' is a 'one way road'. Said by those of higher status to those of lower. お疲れ様 carries such a nuance and can thus be seen as rude when one of lower status says it to one of higher status. The stronger nuance contained in ご苦労様 even more so.)
...That being said, this topic is under discussion in Japan, language is ever changing and it is inconvenient not to have an equivalent お疲れ様 phrase for lower > higher status word transactions.
In regards to your speculation of it being a play of words 様 to さん;
I would speculate that it is much more likely that rather than any cognitive attempt of being witty, it is rather pure linguistic change brought about by the same environmental factors that spawned さん from 様.
To thus answer the question, it is a perfectly sound and linguistically 'correct' phrase to use and its meaning will almost certainly be understood.
Whether the environment such a phrase is in used and the relative social status of the speaker and receiver will allow for it to be considered 'correct' usage in context however... well, this can really only depend on the relationship between the speaker / receiver and how the receiver feels about such language being used at the given time and place.
To err on the side of safety, お疲れ様です／でした is likely to cause the least ripples (= likely to be considered the 'correct' approach)