I'm looking for developers' experiences porting existing webapps into content management systems such as Drupal, Joomla!, or WordPress or creating new ones from scratch with the intent to port to one or more systems.

I'm attempting to create a standardized approach to developing stand-alone web apps under the LAMP environment which are also intended to be ported to a CMS later in their development.

I've tried this process several times myself with DokuWiki, ProjectPier, and LimeSurvey with limited success. In my experience I have sometimes been able to get as far as providing unified authentication but never as far as similar look and feel.

What are your experiences? Have you been able to find a method for tackling this issue? Have you tried to attempt this with your own applications? Have you heard of similar endeavours such as mine?