rectangular grad. ND filters for 95mm lens

Which filter manufacturers make graduated ND fitlers large

enough so that they can be used with large (95mm diameter

filter size) lenses? It has to be significantly larger than

4x4 since the horizon often occurs at the top of the

image rather than the center (so a round, screw-on filter

won't be so useful). The largest ones I know of are by Lee

(4x6).

Sinar makes a series of 3 graduated ND filters to fit their holder: a 0.3 ND, 0.6 ND, and a 0.9 ND. These are very neutral filters that start off feathered and get gradually darker until you are about half way up through the filtered area. They are either 1mm 0r 1.5mm

thick (I forget) and are bought individually. From experience, the more you stop down the hard the swifter the gradation comes into play. Now the hard part: each filter is probably US$125-150, the holder, a three slot design that comes with three snap together lens shade rings that snap into their own fitting at the front of the holder, is about US$200.00, and the adapter ring to connect your lens to the holder is about US$55.00. I have had mine for awhile, so I may be off on the prices. Call Sinar and ask for a catalog. Also check with a company called Visual Departures about the very similar line of filters they distribute.