Looks like this mess might finally be sorted out. Today I convinced NSI to tell me where their host record editing was hidden, and the ultradns.net admin removed a record taht was pointing to the old IP. So now finally the root nameservers are responding with the right answers, and hopfully within 72 hours the changes from my registrair will take hold, and things can finally begin propagating through the net properly. Thanks for all ya'lls patience.