Anyone know if there is a way to search in netsuite for a piece of text such as a variable name and find all scripts that have that text in it?

Not a native way, no. There are bolt-ons like strongpoint that have this functionality. You could also write code that loops your files and looks for strings (plenty of 3rd party libraries for looking for text in files).

It might be easier to download your SuiteScripts folder and use a text search program on your local machine