Sorry, skds1433, but the elites have been replaced and I'm the champion.
Why not replace Blue(aka Gary) at the Viridian Gym? He has high level pokemon in his team. Speaking of which, if you choose this gym, you'll need to either post the other five team members(you mentioned that you wanted a Mew) or I'll make it so that the other five members will be from his Champion team in Yellow version.
Now, here's a list of the gyms, how many underlings they have, how many pokemon they each have(in this order- ex. 2 under. have two each=2'2), who has replaced the gym leader, how many pokemon the GL has.
Violet- 2, 1'2, legolover64, 2
Azalea- 4, 2'2'3'1, houndoomofdarkness, 3
Goldenrod- 4, 3'2'1'3, PIKA2, 2
Ecruteak- 4, 5'2'1'3, TreeckoFan12, 4
Olivine- None, Shinin, 3
Cianwood- 4, 1'1'2'3, DarkLink, 2
Mahogany- 5, 1'3'1'2'3, DarkAvengerCobra, 3
Blackthorn- 5, 3'2'1'1'2, Latias10, 4
Elite Four Will- Dver, 5
Elite Four Koga- probably blitzballchamp, 5
Elite Four Bruno- Philbro
Elite Four Karen- Jason
Champion Lance- Myself, 6
Pewter- 1, 1, KJY2J, 5
Cerulean- 3, 2'3'1, Jennifer(My sister), 5
Vermilion- 3, 4'4'2, Firemaker, 5 *Firemaker, you have to add 2 more pokemon, and what moves are you adding?*
Celadon- 4, 2'1'3'3, Wy Wynaut, 4
Saffron- 4, 2'3'2'1, Flygon Master, 3
Fushcia- 4, 3'1'1'3, Gold Raikou, 5
Cinnabar- None, brendan2004, 3
Viridian-None, skds1433, 6
Ash- Luis(My classmate), 6
There you have it. If you want to be one of these gym leaders, please post here along with the pokemon that you and your underlings will have.