Check out Wawak.com. Wawak Cleaners will often do this kind of work. They'll have a sewing machine that can handle heavy fabrics. I would think you can use a different style button, if you want.

Thank you, Shadylady! Those prices look much more reasonable. The local fabric store was silly expensive. I also found a seller on Etsy (Knopfboutique) with decent pricing. Since I can't tell the quality without seeing them in person, I might order from both.

After more research, it looks like I can use 4-hole buttons and use a spacer when sewing rather than shank buttons? Then maybe I can use my machine if I skip the inner reinforcing buttons. Those wouldn't really be needed on a 40-hole button, would they?

I do think you can use the 4 hole buttons and I don't think reinforcing buttons would be needed. I just stick a pin under the button to use as a spacer. :)

Thanks, again :) I've ordered some buttons and will give it a try.