Upgrading the 990 platform would be a major amount of surgery. On the bright side, Outlaw's reputation and transferrable warranty mean that their equipment holds its value well - you'd likely be able to sell your 990 and help cover much of the cost of a "999" - I got $525 for my Model 950 (which was ~three years old, from the first batch of 950's) when the 950 had just been discontinued, only $175 less than the final $700 price of the new 950.

I wish a concrete date was available. I wonder if i should return it and wait.

Honestly, it's too soon for any manufacturer to give a concrete date for an HDMI v1.3 receiver. The best that we can probably do now is to guess that an HDMI v1.3 pre/pro is still about a year out. If a one-year or longer wait doesn't hamper your enjoyment of your home theater, returning it might be the way to go. I still think it's safe to buy because you can get a lot of enjoyment out of a Model 990 in a year or more, and the resale value will hold up very well over that time.

Outlaw is clearly letting us know that a replacement for the 990 is far off. There is no concrete date to be talked about. That said, you will thoroughly enjoy the 990 now as it is a great processor that does great thing now. Why would you want to wait a long time for great fun now? Enjoy your 990 now, and remember you can never catch up with technology as it is always changing.