As to markings, you have a number of options:
1. The old kits had printed paper decals, which were glued down to the model. I have tried this for some profile "simple scale" models. See the "Garet Scale" gallery for examples made by a number of members, which were decorated with paper decals:
http://smm.solidmodelmemories.net/Gallery/thumbnails.php?album=90 (http://smm.solidmodelmemories.net/Gallery/thumbnails.php?album=90)
Ray has experimented with self-adhesive paper decals, using thin ink-jet sticker paper. In either case, you'll want to properly seal the decals with a clear coat that doesn't make the ink run. TEST FIRST!
2. I have seen models with all hand-painted insignia, and there are a few members here who do that. It's an amazing technique for modelers who are skilled enough to pull it off.
3. Stealing decals from your collection of plastic model kits, or using the spare decals in those kits.
4. Homemade ink-jet decals using decal paper. White is always the difficult color. See the discussion in:
http://smm.solidmodelmemories.net/SMF/index.php?topic=94.0 (http://smm.solidmodelmemories.net/SMF/index.php?topic=94.0)
5. Sending patterns to a custom decal house. Lou has done this a few times. It isn't inexpensive, but they can do the white parts properly.
6. Or build a true all-black ID model and avoid the decal issue altogether. I've only done this once, but Dave T. has built dozens of beautiful models, all finished in a solid color.