There's a mod for Uplink called "Onlink", many of the download links seem to be broken but this forum post links two of the last releases. This is not just a graphical overhaul, it changes mechanics and generally makes the game harder. I haven't tried it, and I'm not sure how it works on Crossover or if it helps with any of the full-screen/font-size issues. Worth giving a shot though if you're not happy with other workarounds for the fullscreen issue or want a tougher version of Uplink to play.