I picked up a lowered seat froma chap on this forum. Basically just a standard seat, with the covering peeled back, foam trimmed down, then covering restapled down. Went this route, as I wanted to share the bike with my wife, whose quite a bit shorter than me (only 5'1 3/4"). The seat is a quick swap, and knocks about an inch or two off the height. Why don't you just get a spare seat off ebay and customise it yourself.