For your consideration...

http://www.linsdomain.com/Otherworld.htm (NSFW)
http://tvtropes.org/pmwiki/pmwiki.php/FanFic/TheOtherworldSeries

A long-running crossover series about a demi-god princess named Aara, her sisters, her descendants, and their harems full of hot anime characters.

There are a TON of fandoms (usually in appearance only) in this. But the main ones are Yu Yu Hakusho, Inuyasha, Rurouni Kenshin, Fushigi Yugi, and Trigun. There's a lot of unnecessary infodumps, a lot of dry sex scenes (and rape... and babies... Anyone who hooks up in this series immediately starts pumping out babies.), and, strangely enough, some noticeable Mormon undertones.

I doubt anyone here would want to tackle this though, since it's just SO DAMN LONG. I've seen mentions of how bad it is. But I don't think any sporker has ever actually finished the whole thing.

http://www.fanfiction.net/s/3402559/1/TenshiTrail
<a href="http://www.mediaminer.org/fanfic/viewst.php/149408">http://www.mediaminer.org/fanfic/viewst.php/149408

This one was mentioned on the Purity Sue page. The blurb for it describes the main character, Sakura Tenshi, as "A "Wish/Chobits flavored" Gratuitous Japanese speaking amnesiac "alluring little kitten goddess yet innocent" angel tenshi-chi with love powers strong enough to destroy Heaven, Hell, and everything in between... in Cowboy Bebop."

From what I've read, the setting and characters of Cowboy Bebop have changed to match the sugary... shoujoness of the main sue and the motley crew of freeloaders (including a dark-sided version of herself) she brings to The Bebop. It also has the most annoying Fangirl Japanese that I have ever seen. The Gratuitous Japanese page mentions such gems like:

-"Naze are we teishing?"
-He looked yuki white with dark ruby and kuro eyes.
-Hentai thoughts ran through Jet’s head.

This is another long one. The first story is 88 chapters long. The author has a web page for the series. But I can't make heads or tails of anything on it due to the shitty site design.

<a href="http://www.fanfiction.net/s/799650/1/DragonBallV">http://www.fanfiction.net/s/799650/1/DragonBallV
<a href="http://www.fanfiction.net/s/1469636/1/DRAGONBALLVSEASONTWO">http://www.fanfiction.net/s/1469636/1/DRAGONBALLVSEASON_TWO

The blurb for this on the God Mode Sue page reads:

"Meet Valis. A female Saiyan survivor. Destined wife of Piccolo. Destined mate of Vegeta. Embodiment of an ancient warrior prophecy, with Inner Senshi-style "warrior women" assistants. More powerful than Goku. Bigger clothes-horse than Cher. Destined Universal Queen."

She's also Goku's long lost sister and, like the blurb says, has a shitload of clothing and hair/eye color changes. (Why? From going Super Saiyan, of course.)

What do you think, sirs?