Oops. Here’s a version with a white background:
Edit: I’m adding a second version, with bolder versions of the Linear A symbols. I did this in a quick and dirty way that doesn’t work so well for all the symbols, but should give a better idea of what it might look like. I used the symbols from the Unicode document, and imported them into Inkscape using Poppler, then did some editing of the SVG by hand to get them bolder. If we decide we like Linear A best (because it’s undeciphered and cultural-appropriation-risk-free), I would go to the trouble of making a new version of each symbol in order to both make them look just right (square, bevel, rounded joins, et cetera) and to make sure there are no copyright issues, but I don’t think it’s worth the trouble unless it gets chosen.
Bold version:
