Is it possible to italicise GUI text without having italic font?

Is it possible to put some kind of skew effect onto text to mimic italics? If not, is there a font builder app that can easily take a whole font and skew it to create a new italicised font?

No, the whole way fonts work, means that italics are part of the file, you can’t generate them at runtime, without rewriting the GUI engine of unity.

With a quick google search, you can find a couple of font editors, this one claims to be the most popular: FontCreator is the most popular font editor for Windows

Hope this helps,