The
Glest Asset Manager technically can do this, but the idea was (presumably) abandoned because of lack of interest. The program only supported vanilla Glest XML, it was difficult to keep up to date, and there was no real community support, as most serious modders found working with the XMLs more versatile. If you aren't already, I'd recommend to use a program with syntax highlighting, such as
Notepad++. Syntax highlighting makes it really easy to see when your XML code isn't valid, as well as makes general reading far easier. Besides that, I'd also recommend you use existing XMLs, or the
XML content on the Glest Wiki as templates, changing what you need.