I know that at one time 
yauponcreek.org
in columbus tx had informal matches on a buffalo at 750 m. and they have large steel plate dingers at 600, 900, and 1000.
that is about the only one I know about maybe thier website can help.
irish

Vbull is right in the eastern half of the United States there are very few 1000 yard ranges and even fewer that are not on millitary bases. I am lucky to belong to a club that has a 1000 yard range but its hard to get on it with the millitary high power shooters useing it every weekend.

40 Rod

Probably a bit far, but Quantico, VA has an available range of 600, 800 and 1000 yards.   

Cat is right, the NRA has the mid atlantic regional at Quantico, VA. It would be a bit of a haul for you but that seems to be a common occurance for those wanting to shoot long range. I was looking at a mention of the Oak Ridge long range match in TN and two competitors came from England to shoot!
I have shot the Quantico Mid Range (200, 300, 600) match but never the long range, but I know several people who do. A few of them haunt this board. If you are interested let us know. Myself or one of the others can get you the contact info for the man in charge. I think the first match is in April and I hope to shoot it this year. Missed it last year because of medical problems.
Merwin

The Cadillac gun club in Michigan has 2 events a year (out to 600yds), here is the news letter with listings (You need to Login or Register to view media files and links);
2008 MRPA Black Powder matches, also they hold long range out ot 1000yd BP matches at Camp Grayling Michigan at least once a year, do not know when though.
MIKE-T

In most Club level Silouette matches you would not be turned away, perhaps not awarded prizes but allowed to shoot for sure.  What caliber is it ?  If big it could be taxing to shoot entire matches.  Generaly 45/70 is as much as anyone shoots Silouette.

My club does not even have a scale

Boats

CC looked at that rifle on CSharps site. It's nice thats for sure. If you will stand for some rambling,

I have the same self imposed restriction. don't want to own anything I don't use.  It is problematical with Single shots however. There are probably 4 ideal set up's depending on the match you want to shoot.  Long range, Silhouette ,Schuetzen traditional, or Modern Schuetzen. Then add rimfire vs centerfire and offhand vs bench or cross sticks and you see what I mean.

C Sharps also sets one up under the original long range rules which is lighter and I believe had a trigger pull restriction.  I have examined many old long range rifles as well as the best reproductions and to my eye they are the most graceful of all. I think 10 #lbs was the rule

It's never a bad choice to get a rifle set up for popular matches, re-sale as well as more shooting options. If it meets BPCS rules long run you would be better off.  I suspect it will weigh if the barrel is 30 inches.  If long is what you want there long range target rife set up for the old NRA rule would easily make weight.  Another weight saver is giving the barrel some taper. Octagon to round with some taper could well make weight even if 32 inches or longer

Unless you need the 45/90 for 1000 yard shooting 45/70 is a better choice. Less recoil more options for matches.  The 40's are match winners if under 600 yards though due less Recoil. That particular rifle to my eye would not be right in anything other than 45 though.  Get down to Schuetzen distances and the 38's for black and 32's for smokeless rule.

At the price of a new Korean Car you ought to get it exactly like you want it.  No doubt CSharps has built rifles in many weights and knows exactly how to make class weights

Boats