Nick
It's not an easy job. The lower plate has three fixings, The outer two locate the plate to the lower cross tube, so if that was the extent of it, an aluminium spacer would be simple to cut and fit. Any depth you like, so an inch would be easy to attain.
But the big problem is the centre fixing at the bottom of the kingpin. Here the kingpin has a male thread, but it's not very long. From memory only half an inch useable space.
So options are:
Get special kingpins made up with an extra inch on the lower thread - expensive solution.
Get a sleeve nut made up which screws onto the bottom kingpin thread. This would look similar to a wheel spacer stud extender. This would allow the bottom plate to be lowered an inch.
Remove the kingpin completely, and insert a spacer between the top of the kinpin and the upper hole in the cross tube end. The top bolt has plenty of thread and could easily accommodate a half inch or so, which with half an inch at the bottom, give an inch.
I don't like the idea of raising the front, because the front looks high anyway, due to the design. raising the rear to 'match' the front is very difficult because the axle is over the chassis and is close to the chassis top, even in standard trim.
