Now, our sources have hinted a very near future announcement (No dates though) followed by a stock availability by 3rd week of May. They also mention that Nokia and Verizon may send invites for a “press event” in US very soon, where Lumia 928 will be unveiled. The promotional offers, on-contract and off-contract prices have been decided and it will be very competitive on the lines of Lumia 920 on AT&T. They also mention that the $25 credit offer news posted by @evleaks is correct and many more such offers will be sponsored by Microsoft to give serious boost to Lumia 928 chances.
We can understand that it has been really hard for many to wait so long for this device, but if no further issues occur at Nokia or Verizon side, by 3rd week of May, Lumia 928 should be in stock at Verizon.