I know there are two different common spacing for S-100 connectors, but I don't know what the spacing is on your Altair. I have a box of new connectors in the garage, but I'd have to know what spacing you need, before I could tell you if the connectors I have will fit.
The ones I have are what I consider to be the more common spacing (I think), and I think they fit all the more modern S-100 motherboards that I ever tried them on. They came from the Compupro Factory. I got them at an Auction, and I will never forget Bill Godbout talking about how much they were worth because of the thickness of the gold plate on them. And that was probably close to 25 over years ago, before the price of gold shot up to where it is now.
I may have a couple of the other ones with the wider spacing as well.
Measure the space between the pins in the two rows, and the distance between the two rows and post back. Then, I'll dig up my box of connectors and see if I have the right ones for you.