I know sources for sights have been mentioned here before but don’t seem to be able to find them.  Can someone please list them for me?  I should say: other than ebay.   
Maybe somebody here can help.  I’m looking for what sight was used on top the extension of a #7 rolling block and a source for it.  I am thinking it is probably a standard Lyman sight less the base but may be wrong.   I also need what the front was.
Thanks, Bob

Other than the special base, the No. 7s I've seen appeared to have a Lyman # 1 sight with a short staff, usually a standard one, though at least one had the special # 47 windage-adjustable staff.  In any case, while I'm not sure what you mean by "the front". my go-to sources (speed never being important) are eBay and oldgunsights.com.

Bill Lawrence

To insure you have enough tang elevation, do a calculation of the proper front sight height (You need to Login or Register to view media files and links)

Ya Vall, you hit the proverbial nail on the head!  That’s been my concern.  Since I will be making the unusual base I will be able to vary the height somewhat but still want to get the correct upper sight if possible.  Looking at photos and measuring as close as I can I think the sight needs to be around and inch tall from the center of the lower hole to the center of the sighting hole in it’s lowest setting.  I did send and email to Mike at oldgunsights asking what he knows and may gave available. 
Please keep the thought and information coming, it’s all helpful.

In my experience, the most common "target" front sight for the No. 7 is a Beach.

As for the rear sight, Vall is exactly right that it's a stubby little thing.  Not having Stroebel's gun sight book or any early-enough Remington or Lyman catalogs. I turned to Rowe's American Gun Sights book.  Therein is reprinted a page from a Lyman catalog that lists the No. 7's tang sight as being stamped "R.S.".  UNFORTUNATELY, while Rowe does show a very clear photo of the sight at about 2-3 times normal size, it's one of the very few sights he does not list a "staff height" for.   So based on similar sights he does size, my guess is that the No. 7's "staff height" is approximately 1.20".  But as Vall says, there is a good chance that Tony Maddox, owner of The Original Sight Co. website, will be able to help you out as much as you need.

Bill Lawrence

bob,  the tang sight used on the #7 was made by lyman specifically for that gun.and seems to have been made in the quantity for those guns only around 350. in 30 years  i have only heard of 1 or maybe 2 correct ones loose and not on a #7. one #7 was special ordered scoped only and the sight was not installed. what we believe is that sight is still in the original box and in a sight collection.i have never had a chance to buy one of these sights,i would jump at the chance.i recently sold the 2 #7's i had .so no help there.good luck.   tony <><   the original sight company.

That's absolutely wonderful, Bruce!  With such a specialized and likely limited market, I had long presumed that only Lyman made sights for the No. 7.  Then here you come with an appropriately-marked Marble's sight ("MSA" stands for "Marble's Safely Axe", not "Marble's Small Arms" as some suppose).  May even the trickles of new knowledge never run dry!

Bill Lawrence

Well, I want to thank everyone.  Bruce, yes the photo is a big help but I’m not sure what I’m going to do now on this gun.  I thought there would be a standard model sight that fit it!  I have Lyman, on a gun, it looks like I need to dig out and study.  I had that sight completely disassembled because it would not extend or retract the staff but don’t remember how everything works anymore.  It seems like I remember a bunch of tiny ball bearing in it thoigh.  Also am wondering if I could take an existing sight and change the staff and barrel lengths?
Sorry for the delayed response, was out of town for the weekend. 
Bob