>Crap. This one should look a little better.
>
>

That's similar to what I had in mind, but remember we would have to account for record level as well as field level rules. I was thinking something more like:

<rules>
  <recordrule enforceexpression="balance >= withdrawal" ruletext="Balance before withdrawal must be greater than withdrawal amount."/>
  <fieldrule field="phone" mask="(999)999-9999" ruletext="The phone number contains illegal characters."/>
  <fieldrule field="phone" required="true" ruletext="You must enter a telephone number."/>

  .
  .
  .
</Rules>