idea.html

<template name='form'>
  <input name='email' value={{email}}>
  {{#with validate 'email'}}
    {{message}}
  {{/with}}
</template>

idea.js

EmailForm = new ShadowModel({
  collection: new Mongo.Collection('example'),
  fields: { //basically a transform + schema for instances
    email: function (value) {
    var email = someEmailValidator(value) //readme shortcut -_^
    if (email) {
      if (email == 'gmail') {
        return this.valid('is a Gmail email')
      } else if (email == 'apple') {
        return this.valid('is an Apple email')
      } else { //and so on
       return this.valid('is email')
      }
    } else {
      return this.invalid('must be an email') //you would want to be more descriptive...
    }
  },
  ...
 }
}

Template.form.helpers({
    data: function () {
        return EmailForm.new() 
    }
})