It is often a problem that bike shops have when they come to building unicycle wheels, their truing stands do not fit on to unicycle wheels. This is due to bikes having internal bearings and unicycles having external. There is a solution with the KH 42mm truing stand adapter.
These work great once they are set up which takes a long time to get right and have difficulty with changing width of hub. In our office we have these set up for truing wheels KH wheels or when we do not have the frame. What we prefer to use for the majority of our wheel builds is our simple home made seatpost wheel truing stand.
Not only is this stand incredibly simple to build but has an advantage over using a traditional truing stands. As it aligns the wheel to the seatpost, not the frame legs so the wheel is absolutely correctly trued for riding. For riding a unicycle this is the most important criteria.
Our stand uses a 300mm long 25.4 seatpost screwed to a block of wood. We then have a small part of an old frame with it's seatpost clamp just slipped over it. Although you can use the frame's own seatpost clamp to secure it to the post if you want. When we are truing a wheel in a 27.2 frame we use a shim.
When truing the wheel you use the seatpost to align to the centre of the rim. This will guarantee that the wheel is both round (not egg or centred vertically) and true left to right. This solution does not work for all frames as you will need a frame that has a seatpost that passes through the crown.