Account creation user experience/SignupAPI

Is there anything we can leverage from Extension:SignupAPI?

includes/verification.js
has jQuery (mostly) JS to:
 * passwordStrength to evaluate password
 * checkRetype for second password entry match,
 * checkUsername just complains if username not entered

It also makes an $.ajax post query to the SignupAPI's API to validate fields.
 * HTML5 has email fieldtype to do it for free on recent browsers.

ApiSignup.php
Given a lot of API signup parameters, calls its own addNewAccountInternal function.

It then runs some hooks for AddNewAccount, UserLoginComplete, and BeforeWelcomeCreation. These might generate some welcome HTML, not sure how this gets returned to the caller.

ApiValidateSignup.php
(Same comment as ApiSignup, "Unit to create accounts in the current wiki", which is wrong)

This validates a single field: username or email or passwordLength (sic), returning a result message (good or bad) and icon (Checkmark or no mark). It calls MW User class static functions like User::isValidUserName and User::isValidEmailAddr and checks password length against a global.

other
Adds some sourcetracking hooks in a SignupAPIHooks.

Implements Special:UserSignup page
Try turning this on

source tracking
if ( $wgSignupAPISourceTracking )
 * adds a sourcetracking table to the schema
 * adds a hook on 'Personal URLs' for source tracking