I feel like I see posts on here or Facebook, as well as people asking me in person, and people always want to know where you can get Impact parts in the US.
I know that Unicycle.com has started stocking the Impact saddles, but for other parts and whole unicycles, you guys should check out Compulsion Cycles. He has trials frames, saddles (white and black), cranks, seat posts and whole flat and trials unis.
Also, Joe (the owner) often stocks things that Unicycle.com does not stock, or still has stock when they run out.
P.S. If you haven’t checked out the new impact seatposts, they’re awesome. I’m a muni and distance guy and I almost had to buy one.