hey there, there is a good chance that no one is completely stuck anymore! if you are S-ON with hboot 1.45.0013, indications are that you can flash a full factory PG59IMG.zip of the new 1.55.531.3 ROM, and then after that the HTC Unlock tool will work like it is supposed to. and even tho that isn't really as good as S-OFF, you can still root and flash some custom ROMs.
we still need someone with S-ON to verify that the hboot will allow the flash(I am S-OFF and i verified that the HTC tool DOES work after flashing this). the file is located here:
[ROMs]Leaked HTC Android ROMs - xda-developers
(click on the link for generic releases, then find the file for Doubleshot).
still waiting for someone with S-ON to verify... but a friend with S-ON said his hboot DID in fact prompt him to update with this file, he just hasn't done it yet. it is worth noting that flashing this WILL be a full factory reset/wipe of your phone, meaning you will have to reload your apps and such.
anyway, just wanted to pass on the news
over at XDA people are working on getting S-OFF as well, but there is no guarantee it will happen, but hopefully it will soon.
UPDATE: this has been confirmed to work! even if you are S-ON, you can flash the PG59IMG.zip thru the bootloader, and then the HTC Unlock tool will work.