Would also love to see proper UDP support for this official WiFi shield. I also have a Linksprite WiShield 2.0 (Asynclabs compatible), UDP works fine there, but the library is a complete mess and not fun to work with.
I was looking for a easy to use tool to convert images to arrays. So I ended up writing my own. It's just a single file so you can download it if you want, and runs in your browser: http://logotype.se/image-converter-arduino/
Please test it and let me know if it works. I've tested it successfully with a 128x64 display.