Dinosaurs Valid idea, dinosaurs are pretty awesome. Although, it's been quite some time since Jurrasic Park was released, and dinosaurs since then have not made many inroads into culture or any sub-culture. Dinosaurs are awesome...but do people really care??
Mutants
If you mean as in X-Men mutants, then yes this would appear to be a likely contender. The X Men films and comic books have always been popular with nerd's, and secondly it also has Patrick Stewart, who is already a well established internet meme.
Samurai
A possible extension of the ninja meme perhaps? Still, i think my problem here is that Samurai are noble, honourable warrors, and i don't think nerds can relate to that. Look at the other types of warrors that nerds relate to- pirates and ninja's, the Ninja's are dark, shadowy and mysterious, and the pirates are rougues outside society. Samurai are not mysterious, shadowy or rougeish.
Scots Possible choice, the Scots seem to have that innate quality of kick-ass awesomeness, just look at characters like Soap MacTavish.. he must be Scottish! There are plenty of jokes surrounding the Scot's as well, perhaps things like kilts and haggis creatures could become sub-memes?
Gladiators These chaps could sit well within the nerd psyche. They are rebel's, they are lone fighters, and damn good ones too, so they fill the check box of being social outsiders. They are also forced to fight to the death before the masses, for the amusement of mainstream society. I think perhaps nerds could relate to that.
Alan Cumming Who?
Luchadors Who?
I googled them this time..they seem like wrestlers. I think the problem with these guys are that they are all about over-the-top machoness with big huge arms and chests. I'm not to sure how many nerds would want to relate to that physice.
Really though, you carn't just all come together and vote on a new meme like it's the UN or something, only 4chan has the power to create memes.