All in one CMS package

I have a fairly far fetched idea but i thought i’d get some opinions to help me get started.

The idea: To integrate or develop an all in one cms package (Shoppingcart, Forum, Blog, Gallery) that is easy to maintain for the website owner/end user.

My question is, what is the best way to approach this. Sitepoint is a perfect example of this combination, it has a forum, article/blog, shopping cart etc.
I see that this forum is vBulletin, so i am assuming that that sitepoint uses purpose built applications and integrates them together. The issues i can see with this is version updates, shared user database and compatibility between applications . Everything updates at its own pace so i could imagine it would be a headache keeping everying up to speed. The ability to bridge features between the applications could also be an issue such as access to the same galleries etc etc.

What do you guys recommend? Reinvent the wheel and build an all in one package. Or pick opensource applications and integrate them together?

Integration time is going to be much less than development time on even one component of that list of packages. You could have one employee integrate 3 systems in a month, or a team of programmers to build the 3 from scratch over months or years. There’s going to be maintenance either way, so that’s not a good excuse to reinvent the wheel. You need some kind of serious business need to justify the orders of magnitude higher man hours replicating what already exists would entail.

Even the idea of having one CMS with those 4 components integrated already exists. WordPress, Joomla, and other CMS’s have plugins that add forums, galleries and shopping carts to a base that supports blogging and static articles. All for free, with a single integrated database, and automatic update installation for all the components.

If you have the time to do all that custom development, put it into what doesn’t already exist, into what will make your site/business different. SitePoint uses vBulletin for its forum, WordPress for its blogs… but when it came to building a marketplace for buying and selling websites, that’s where they did something custom. Crowdsourcing design contests a little unlike ever before, that’s where they did something custom. This forum is just like any other forum in terms of functionality, they put the custom development time into the things they do different.