Nothings impossible. I know lowering kits are popular on HDs. Maybe if you checked they could advise who makes them. Or....... get out the old engineering book. Can't be that hard with a rather simple suspension.
Short of letting the air out of the suspension, I would think about the only thing you could do is go with a smaller tire/rim size.
Does anyone know of shorter front forks, and modified rear swing arm, that would allow a lower ride height?
I was told by a very reputable shop that the Goldwing is one of the few bikes that is very particular with tire sizes. They very strongly recommended staying with the stock tire sizes and I have not been disappointed. My bike also sits a little too tall for me as well. I tried taking air out of the suspension but that just made the ride rougher. About the only way that I know of adjusting ride height on the older bikes (mine is an '83 Interstate) is to get a custom seat that is shorter. If anyone has anything better to offer, I will be interested. Thanks.