I do not -- but I have know / read about a few ppl who have, including my grandad many years ago ..
I think you might get more response if you post this question on the IA site ..
From what I recall reading in there in the past -- my understanding is that the urine-thing is the hardest stoma to live with cos it is so WET and thus likely to get under the flange and irriate your skin -- which it is liable to do, being so acidic ..
I also think the urine one can be tapped out to a bottle by your bed for draining in the night, to allow for better sleep without having to get up to empty it ... I dunno if you could achieve that with a combined output?
My personal feeling based on that would be to keep them seperate, but obviously it adds another level of daily chore to the bag routines and makes feeling sexy a bit more of a challenge, and you are going to be very compromised in that department anyway
How common is that dual output solution? You might have to hit Google and take the rough with the smooth in terms of what you have to read to get informed opinion on this issue
all the best,