I am searching at creating a custom web application for any client (a specialized auction, within this situation), and we are evaluating with a couple existing Content management systems because the "scaffold" for that application.

The justification is always that for a lot of custom web application projects, some 70% from the code written gets into to adding Content management systems features, user management, and fundamental admin CRUD. Most probably, as we begin with a current Content management systems, then individuals to components will be built.

We have made the decision to stay with PHP for distribution and deployment reasons. The very best CMSes we are evaluating are Wordpress, Drupal, and Joomla. Here's our analysis to date (indexed by order):

Pros: Dead-simple design. Very popular and understood. Very solid recent security history.
Cons: Possibly a tad too simple -- will it be produced to operate?

Pros: Potentially more friendly to custom database integration. Decent security history.
Cons: More complicated and hard to know.

Pros: Popular and well understood.
Cons: Some security concerns

Once from the greatest issues we are accumulating against, and what we should aspire to gain in the S.O. community is knowing how easily it may be personalized to become a custom application. For example, once the client adopts his administration area, is he going to obtain the impression that it is really an, "auction having a built-in wordpress Content management systems", or could it be a "wordpress site by having an auction wordpress plugin"? We are wishing for that former as opposed to the latter. But will it be achieved?

Or possibly shall we be searching within the wrong direction? Should we be searching rather at something similar to CakePHP? (Observe that options like RoR and Django are off-the-table due to distribution and deployment reasons.)

Here are a few related (although not identical) questions that have some helpful information:
Utilizing a Content management systems to create an internet Application
Content management systems for custom application

Unless of course you are doing something radical you are likely to be better of utilizing a Content management systems (in complete agreement with Tom Wright above).

I'll help out for Drupal. Its a very capable Content management systems that forces some first class websites like http://world wide web.whitehouse.gov (The United States President's Official website). That itself talks volumes about its scalability, reliability and security.

Take a look at http://drupalsites.internet to determine an entire group of websites produced in Drupal. Once in Drupal you'll get access to probably the most active towns available to have an free project. This community has created over 2000+ free modules (or add-ons) to satisfy needs that can't be satisfied by vanilla Drupal.

It is a fact that Drupal has a sharper learning curve than Joomla or Wordpress. But Drupal, In my opinion is much more effective than Wordpress and Joomla. Once you have mastered basic principles of Drupal it's very easy to unveil features. The entire Drupal system just feels consistent. Some CMSes are a never-ending number of one-off modules that simply need to be set up this way. Drupal has some effective modules like Sights and CCK, that, once mastered can help you accomplish a lot of stuff that might have needed a variety of hacks/add-ons/custom programming in other CMSes.

Joomla includes a status to be simpler to understand but ultimately a hardship on building truly complex and massive community based sites. Wordpress, though fast ageing with version 3. continues to be a ways away in becoming as feature wealthy as Drupal/Joomla. Then you will find another approaching CMSes coming -- take a look at Packtpub Content management systems honours -- you can observe good quality CMSes listed there.

Basically it comes down lower for this -- CMSes like Drupal are made to support mainstream website needs. If your internet site is not radical (present day twitter or foursquare equivalent) stay with Drupal/another Content management systems. The expansion occasions are simply seriously reduced. Only one time you are feeling that your work isn't practical inside a Content management systems if you undertake a framework like Cake, Django etc.