There is a very cool new online Joomla Template Creator at Template-Builder.com.

The application is currently in beta and looking for testers

It's very close to using a desktop application and specifically designed to make Joomla Templates with precise control.

This SAAS Joomla Template Generator will be an economical alternative to desktop apps allowing the purchase of single templates or subscriptions.

To access the free beta sign up at Template-Builder.com