When you say Assurion "can't" get you a Pro, does that mean they are willing to give you a Pro if one becomes available, or are they saying no to an upgrade to the Pro? If they will give you one, you'll have to wait like everyone else. If they won't upgrade, it gets harder.
Tell them you specifically got your Mogul because it had both MicroSD and WiFi, therefore neither the Touch or the Diamond are of any use to you. I'm sure you need the additional storage capacity the card has for your work where you use the WiFi to connect to your network
Ask them what it would take to get you a Pro.
If you can't get anywhere with Assurion, try Sprint customer service. You may have to work your way up through the levels until you get to retentions, but they might be able to help you get a Pro if you explain Assurion can't supply you with a replacement equivalent to your Mogul. Be prepared to pay as the Pro is definitely an upgrade to the Mogul. Having dealt with retentions on 2 separate issues involving 4 phones, I have been very happy with their ability to arrive at a solution (just my 2 cents worth).
PM me if you get stuck and I can send you a direct phone number for retentions. Good luck.