I've been asked to make a few of my chamonix extension brackets for the 45n-1 & 45n-2. Constructed of 9-ply baltic birch, approximately 8 1/2" long x 2 1/8" wide and increases the cameras extension by approximately 5". That's more than enough for a 450mm or a 250mm in 1:1 territory. Can be mounted anywhere along the focusing track. $75 shipped worldwide. Payment by paypal or postal money order. PM me for payment info.
my version of the chamonix extension bracket by vinnywalsh.com, on Flickr
shown mounted in longest position.
cham-ext-on-camera by vinnywalsh.com, on Flickr