WordPress MU

I have a copy of WPMU installed on a local test server. Basically, what I'm wanting to set up is a complete portal powered by WPMU. It might sound easy at first, but when you look at yahoo.com as a simple portal the task seems daunting.

I need my users to sign up for a WP account as an email address, similar to what you see at Google. You sign in with your gmail address and get access to all the stuff they have there. Same thing applies with WP, I need a webmail account to automatically be created for them. I also need to make it so that they sign in using their email address. I'm planning on using squirrelmail for their webmail.

I will also need to be able to set up a forum, on my local machine I have bbPress installed but I have many issues with the links and I will need to set up the email creation and email as login on bbPress as well, but that's something I'll need to post at their forum.

I use the subdomain setup on WPMU, but WPMU seems to override anything else I might have set up on a different subdomain or even directory. Is there a way to reserve a subdomain, or a directory? I want to continue to use the URL rewriting but I don't want it to completely take everything over, the ability to add exceptions to it would be nice.

At the moment, I have the revver video plugin installed for video submission and a youtube-like community, but that doesn't upload their videos to my server. Does anybody know of a plugin or non-plugin software that would serve this purpose? The ability to use it without their branding would also be great, as I'm wanting the entire portal to work seamlessly and look seamless to the end user.

Looking at all of the things I still have yet to do, it can seem like it'd be easier if I just code it all from scratch. That would take me a very long time to do, I'm not a pro at this stuff xD I've never even messed with URL rewriting before until a week or two ago, just before I started working with WP. I have basic PHP/SQL/XHTML/CSS knowlege.

[edit]
I almost forgot, I don't want the end users to be forced to log in more then once.

Wow ...

Yeah, it's kinda like that.

I'd be inclined to find a piece of software that's closer to what you want to do (ie; a portal) than rewriting half of WP.

The way I see it, Yahoo is mostly feeds. MyYahoo is a little more customized. I have done a very simple version of both a long time back- a really simple version.
In fact, I had multiple panels, each of which had multiple tabs, each of which had news feeds from different sources (like Reuters, CNN, NBS, NPR).
The front page also had a RSS feed from the forums and one from blogs section of the portal.
So why did I give it up? Not worth the effort :(
Switched to WP, never looked back. I cannot stress enough the significance of open-source and plugins. And a platform that is used, discussed, and supported by such a large community.
DynamicDrive was a lot of help in that project. Stuff like AJAX tabs, slide-down/up DIVs, SimplePie integration...User management and blogs were through WP (BBPress for forums), but I was not smart enough to use plugins. Instead, I hard-coded stuff. Feel like an idiot now :(

In my travels online, I came across an uber-theme (theme overloaded with plugins galore) that was basically Y! in a box. I have searched my bookmarks and G for the link but couldn't find it -but it's out there...

but WPMU seems to override anything else I might have set up on a different subdomain or even directory. Is there a way to reserve a subdomain, or a directory?

http://codex.wordpress.org/Ignore_Some_Subdomains_With_WPMu

As far as the URL rewriting goes, there are many ways of managing this including plugins. I offer the link as proof of concept, not as the solution you're looking for. For this and the video plugin solution, search through the WP Extend/Plugins directory...

pumpkinpatch,

Yahoo is not what I'm going for exactly, but a one-stop web site is what I'm after. I want to give the end users very little reason to have to navigate off the site.

musnake,

Thanks! Modifying the httpd.conf file and adding the virtualhost worked perfectly. bbPress still gives me hell with using the pretty links, but at least I'm not having any 404 errors on WP anymore when using them. Now the problem is solely with bbPress, because I click a link when using pretty links, and it just stays at the forum index.

The choice of video plugins, last I looked, was pretty limited though I suppose I'll look again. I could have easily missed a bunch, knowing the way I work. xD

Thanks to everybody for the responses, I appreciate you all and please keep them coming!