I'm a Flex / Flash Builder developer and for the most part when developing a backend we tend to use Zend AMF or AMFPHP. The AMF protocol is used because it is much faster than other web services / protocols.
Can the mobile version of appcelerator consume AMF services?
Titanium supports ruby scripts, so i'm guessing that it will be very simple to include an AMF serializer and deserializer with the Rubyamf plugin.
I've been looking to solve that same problem Irving.