I'm going to leave this post and list here because it can still serve a useful and helpful purpose. If you want to suggest a new collaboartion between Adult Swim and the creator of one of your favorite shows, you may use this list as a reference.
3 South: Ron Hughart & Mark Hentemenn
Action League Now!: Tim Hill
the Adventures of Jimmy Neutron Boy Genius: John A Davis
Aeon Flux: Peter Chung (also designed Reign the Conqueror)
Angry Beavers: Michael Gerard
Beavis & Butt-Head: Mike Judge (also created King of the Hill)
Bob and Margaret: David Fine, Alison Snowden
Brothers Grunt: Danny Antonucci (also created Ed, Edd & Eddy for Cartoon Network)
Celebrity Deathmatch: Eric Fogel (also created "the Head")
Clerks: Kevin Smith
Clone High : Phil Lord & Chris Miller
the Critic: No real set creative team, starred Jon Lovitz.
Daria: Mike Judge spinoff series written/directed by various people
Dilbert: Scott Adams (based on his comic strip, series had various writers & directors)
Dr Katz Professional Therapist: Jonathan Katz & Tom Snyder
Duckman: Various writers and directors.
Fairly Oddparents: Butch Hartman
the Head: Eric Fogel (Also created Celebrity Deathmatch)
Invader Zim: Johnen Vasquez (also created the comix; Squee, and Johnny the Homicidal Maniac)
the Maxx: Sam Kieth (based on his comic)
da Mob (MTV): Phillipe Balmo
the Ren & Stimpy Show: John Kricfalusi (Also created 'the Ripping Friends' for Fox [later picked up by Adult Swim), and a couple of parody Yogi Bear shorts for Adult Swim)
Rocko's Modern Life: Joe Murray
the Sifl & Olly Show: Matt Crocco & Liam Lynch
South Park: Trey Parker & Matt Stone
Spider Man the Animated Series (MTV): Marvel Comics (various directors/writers/producers)
Spongebob Squarepants: Stephen Hillenberg
Super Adventure Team (MTV/Marionettes): William Bison
the Tick: Ben Edlund (also created a short-lived live action version of the Tick for Fox)
Undergrads: Pete Williams, Jerry Popowich
Yakkity Yak: Mark Gravas
There are also shows that CN actually has the rights to, but aren't age appropriate for Adult Swim, again, it is asked that you DO NOT recommend these shows, but rather, perhaps new shows designed by their creators for an adult demographic instead:
Codename: Kids Next Door: Mr Warburton
Cow & Chicken: David Feiss
Dexter's Laboratory: Genndy Tartakovsky
Ed, Edd & Eddy: Danny Antonucci
Grim & Evil: Maxwell Atoms
Powerpuff Girls: Craig McCraken
Samurai Jack: Genndy Tartakovsky
Sheep In the Big City: Mo Willems
Time Squad: David Wasson
There are a handful of animated comedy shows floating around out there. These are the kinds of shows that AS might be more able to get ahold of (but aren't necessarily going after, these are just examples):
Committed (Canada): Michael Fry & Matthew Salsberg (Starring Dave Foley, Catherine O'Hara, Eguene Levy, & Andrea Martin) / 13 Episodes.
Free For All (Showtime): Merriwhether Williams / 7 Episodes
Funky Cops (Fox): In development
God, the Devil & Bob (NBC): various writers/directors starring Alan Cumm1ng, James Garner, Laurie Metcalf and French Stewart) 13 episodes (only 2 aired)
Kevin Spencer (Canada): Dave Bigelow, 50 "10-11 minute" episodes
King of the Hill (Fox): When it wraps up I'm sure AS would like to get it's hands on it.
PJs (Fox/WB): 41 episodes.
Sammy (NBC): starred David Spade, Bob Odenkirk, Maura Tierney, Andy d1ck, Jeffrey Tambor, Julia Sweeney and Harland Williams. was cancelled after 2 episodes aired.
the Simpsons (Fox): I think AS wants to get it's hands on this sooner or later.
Spicy City (Ralph Bakshi): 6 episodes
Stressed Eric (BBC): 13 episodes