I don't know how Tarlanon feels about this, but Im more concerned about people using all of the events and stuff on the techncal side.
I don't know if you've downloaded and/or looked at the 1024x768 default art, but there is a bit of a divergence in the official default art, namely the walls and backgrounds. It may be that Ziroc's backgrounds will be supplemented with 640x480 versions of the higher res set. To use either the backgrounds or walls, you just need to scale them to 50% and they are good to go.
To state it more clearly, using the default art does not mean using every single piece of the default art set.
We would like you to use as much as possible and supplement it with art from other sources, such as listed above in this post.
This was a really good question, Jadefang. Thanks for asking and I look forward to seeing your entry.