Seth, I was planning to use the chip LEDs from Evans Designs (Forum Sponsor) I have to measure the bulb size on the lamps. I would slice off the shade, drill, glue in the LED, reattach the shade and then run the wires along the goose neck and into the building. The Nano or Pico look to be about the right size. MTH uses wheat type lamps in their passenger cars. I just think they use too much power off the transformer.
After watching a video on lighting HO passenger cars, I like the idea of using magnetic wire connectors between cars, to minimize the need for diodes and to remove some of the power pickup rollers.
Regarding making signs - there are a number of good videos on Model Railroad Academy. Sometimes you can get an annual subscription for next to nothing. Some videos are free. Not sure if the link will work for you, but this one shows how he makes signs from old magazine advertisements. Neat process.
