Yup, unfortunately this was always on the cards.
If unrevoked can't do it, you could try
this beta from the alpharev & unrevoked teams. But note: this is beta release software, and since Desire hboot 1.02 is
new, by definition nobody will have tested it with this hboot version. So everything would be
at your own risk. Personally if I was going to try this I'd contact the devs first.
Or you can wait it out - they've cracked a lot of previously secure HTC devices recently, so I suspect this one will fall soon enough.
Note: this isn't a rooting tool in the way that unrevoked is. That roots your current ROM and installs a custom recovery. This S-Offs your phone (bypasses NAND security) and optionally installs a custom recovery. Recovery will let you flash a different ROM, but there's nothing here about rooting your current ROM that I can see. But this looks like the way we are going from now (and once someone releases a rooted version of this ROM the end rtesult will be the same).