It's possible but we were not able too when the last update happened three months ago (Viacom HD Suite and Hallmark).
Another thing I thought of is the last update was exactly 3 months ago.
Hopefully, we do not have to wait until September 8 for the next update but at least if we do, it will probably be a bigger update.
Right now, were looking at the above mentioned channels (GMC HD, Sportsman HD, Discovery Kids HD, DIY HD) along with Gol TV HD, Ovation HD, The Cooking Channel HD, Sundance HD and maybe some of the new HD Showtime channels.
My hope is they can cut renewal deals with Lifetime, TWC and Tru TV so we can have HD versions of those channels.
There is also a chance Time Warner and the NFL work out a deal for NFL Network in August and that would be icing on the cake.
In the end, I expect a big update in September and it might be the last one as we could have all of the major HD channels with the above possibilities.