Third Party Developer PhoneFusion Offers To Create Visual Voicemail for Palm Pre
Since the Instinct has it, we know it can be done. I don't see any reason they wouldn't be able to complete this fairly rapidly.
I will stick with giving out my Google Voice number for the transcripts (VVM, SMS, and email), switch to my office phone and back during a call, listen in while they leave a message (and change my mind and take the call based on what they say), turn recording off and on during the call, conference in up to four incoming calls at once, free forwarding, etc.