Intressting tool! I'll try it out sometime after whe weekend and let you know what I think :)

BUG: Fontstring
 

My client doesn't recognize CreateFontString as an existing function. Might want to change it to a CreateFrame instead. Thank you for this wonderful tool. Has helped me learn widgets a lot! :P

EDIT: Nevermind. It is because you did not put its parent BEFORE CreateFontString. It was designed to be used as following:
But you did:
My suggestion is to change what you have to:

Looks like this could be great. I've found AddOn Studio too big and inflexible. Is there a way to get a frame to inherit from another? Also, I'm not familiar with Silverlight, but it would be great if this could be downloaded as an executable.

Thanks,

Making it an executable is actually very easy with Silverlight. Because Silverlight apps are ran client side, they are the perfect candidate for a local app. I have this feature enabled for most of my apps developed with Silverlight, but haven't enabled it for this one just yet.

I haven't visited this project for some time, and plan on picking it up once again. I didn't want to dive to deep into it just yet because Silverlight 4 was just released with Visual Studio 2010. Here soon I'll be updating it.

Since you work with VB.net you could also create a new XML file in VS, link to the latest UI.xsd which you can extract from your game files and let the IDE handle the rest or use any 3rd party XML editor to validate against the WoW XML schema. Nice work anyway.

In case you meant "Doesn't work in 64 bit browsers", then I can tell you it does (Tested with IE 8 and Chrome 7)

Anyways, it looks quite decent, but I'd appreciate an Import feature, allowing me to import my Lua or XML code to have your App draw the Frame's layout.

As a suggestion, I'd like to see the actual in-game textures used, as it makes it far easier to familiarize with the frame, and design it in that way.

Maybe you could add support for AceGUI export as well?