I went out and got a seat and post and tried it out.
I am using my handlebar with a Kalloy seatpost (unfortunately 24.0 so I needed to shim) and a KHS saddle from the cheap bin. This is on my 26" MUni because that is the only unicycle I have at the moment.
It took me a while to get the seat angle and height right but I eventually found a setting that was fairly comfortable. I had to turn the seatpost backwards to let the seat sit flat when I rode.
First thing I noticed was how free it felt on the front part of my crotch. the seat felt like… I was riding a bike. All my weight was on my ‘sit bones’ and the handle. The next thing I noticed was an absence of rubbing. I never really thought of it before but my legs rub allot on a unicycle seat. Since there was less between my legs I found that I was riding with my knees closer together and seemed to spin (160mm cranks, HA!) fairly smooth.
So far it was awesome. I could see myself going indefinitely without discomfort with a better seat. I can only ride for about an hour strait before I start getting discomfort with a unicycle seat.
Then I straitened out taking the weight off the handlebars. It went from weight on my hand and sit bones to weight on my legs and a single point in my crotch. Not comfortable at all.
I think my handlebars are a bit shorter than ideal for this setup but I really liked what I had experienced so far as far as a road setup is concerned. I think that my next road unicycle will have a long handle and bike seat setup.
A bit random but I think that something like the WTB Laser (which I have on my bike) would be the ideal seat for this. A bit softer than a pure road/race seat and actually designed to be sat on for extended periods of time unlike a downhill seat.
and here is an old picture with my handle for those not familiar with it. I don’t have a camera to take pics of the current test setup.