No, no, no, forget about doing crossovers based on compatible 
characters or similar storylines!  The *real* trick is putting 
together two ideas that have nothing to do with each other.  
For example:

Tenchi Moon!
		Tenchi as Derian
		Ayeka as Serena
		Ryoko as Raye
		Washu as Ami
		Sasami as Reenie
		Mihoshi as Molly
		etc.
	and retell the Sailor Moon series like that.  (Ok, I 
	don't know the orginal SM names.  It's *not* my favorite 
	series.)

SMC (Sailor Moon Crisis)
	Crystal-Tokyo is under attack! Can the Saber Scouts save 
	humanity from the Genom-verse?
		Serena as Sylia
		Luna as Mackie
		Lita as Priss
		Ami as Nene
		Raye as Linna
		Molly as Irene
		Artemis as Dr. Raven
		Chad as Vision
		Derian as Leon McNicol
		Queen Beryl as Quincy
		Jedite as Brian Mason 
		Nephlite as JB Gibson
		Malachite as Largo
		Zoecite as Madigan

And some other (bad) ideas:

Oh! Gunbuster		(AMS! x Gunbuster)
801 Y.U.A.		(801 TTS Airbats x You're Under Arrest)
Project AMS!		(Project A-ko x AMS!)
Devilbuster Yohko	(DHY x Gunbuster)


Just some mindless ramblings...just don't write them, okay? ^_^

Dewa,
Shunsuke

--
"Veni, vidi, vici."  ("Came, saw, conquered.")   - Julius Caesar
"Veni, vidi, visa."  ("Came, saw, purchased.")   - Julius, seize her!
"Veni, vidi, vomiti."  ("Came, saw, threw up.")  - Julius' seizure.