I have the luxury of living car free in the Boston area, and I’ve been looking into hauling unicycles by bike to get to nearby trails.
I remember seeing a picture of a Trailgator (USD90) here, but you’d need to install a chunky tow kit on each unicycle.
Not happy with that solution, I did some more digging and found the MBB shortboard surf rack quite a bit cheaper (USD60 on Amazon), and after 50 miles of hauling a 29er, it’s exceeded all my expectations.
The rack mounts to the seatpost and comes off via quick release. You have to experiment with uni placement, but once you figure it out, the uni will sit snug against the foam padding (I recommend using a bungee cord anyway) and won’t interfere with pedaling. The whole setup looks extremely lopsided, but it is surprisingly stable on my touring bike. It feels like I’m riding with a single loaded pannier.
My only concern is the load capacity, since my 29er is at least twice the weight of a surfboard. So far, the rack has held up; but I’ll be sure to post if it fails!