So ended up having a glass shop come out and install some new glass.
I found a window that had been pulled out of an old home (about the same age as mine, it appeared), and pulled the glass from it. Ended up being quite easy as it was held in place with calk and a bit of molding. The shop cut it and installed it for me, also fixed another window that had been calked (poorly) but not glazed in. Total price was $100, would have been about $126 if the old glass had broken and I had to get a new sheet of glass.
The price of laminate made it not worth it, plus the groove where the window sits wasn't deep enough.
Looks like some removable storm windows are the next step, going to go the old fashioned route where they hang from the outside. That should be nearly as good as converting the windows to double pane, at a fraction of the cost and without destroying the way the home looks. Plus the windows are actually designed for them, so they should look like they were original.