Lots of spambot accounts?

[Chenier]

Do you know of any extensions that could do that sort of thing? It has to be a supported extension. Hand-coding our own modifications to MediaWiki isn't a viable solution.

Sorry, I don't know much of extensions for wikis. Just thought maybe it'd exist somewhere.

[Draco Tanos]

http://www.mediawiki.org/wiki/Extension:ConfirmEdit

Not entirely sure if it goes to account creation (which I hope it does/can), but this might work.

Edit:  It does!
There are five "triggers" on which CAPTCHAs can be displayed:
'edit' - triggered on every attempted page save
'create' - triggered on page creation
'addurl' - triggered on a page save that would add one or more URLs to the page
'createaccount' - triggered on creation of a new account
'badlogin' - triggered on the next login attempt after a failed one. Requires $wgMainCacheType to be set to something other than CACHE_NONE.