With some tweaks you can easily create a neon text effect in Fancy Product Designer like in this demo.
Right now it is not possible to set multiple text shadows on a single text layer, but with the help of the "Text Link Group" option, you can create several text layers with different text shadows and link the text content and properties.
It is important that you set the same "Text Link Group" value for all 4 text layers and disable the "Editable" option on the last 3 text layers. So only the first text layer can be change. But as soon as it will be change, the other text layers will be automatically changed as well.
In order to change not only the text content, you also have to select all "Text Link Group Properties" in the Advanced settings.
But to keep thing simple, just download the full FPD demo and import it via the Products page.
Following Google Webfonts are used in the demo: