It all depends on when the devs can work on it. Since they're close with v3...it shouldn't be too long.
Actually, motoxcreature's boy-genius cousin has already rooted the phone weeks ago; but it's impossible to predict how much time it will take
to document the method.
Seriously now: the Eris has never been rooted. Not 1.5, not any of the 2.1 leaks. A no-security bootloader upgrade was leaked by someone who worked for HTC or VZW, and that's how rooted ROMs got loaded on to the phone. Surprisingly, though, knowing all that does not help to predict if or when it will happen. Could be tomorrow, could be never.
It's not like baking a loaf of bread, where you know exactly what steps are required, and about how much time is needed for each step. It's more like wiggling the doorknobs on random houses to see if they are unlocked... and only if you find an unlocked one with a poodle inside are you done.
Personally, I think an interesting query to pose over on XDA would be "Post a reply if you have personally attempted an application, bootloader, or kernel exploit against any HTC release (or leak) on an Eris in the last 7 days."
I think you will probably be able to count the replies on less than five fingers.
Don't get me wrong, I would love to see someone succeed at it... but I think that there is an impression that a lot of devs are working frantically to get root for the leakers, or even for downstream 2.1... and I am skeptical that that is the case.
eu1