I haven't seen this mentioned in awhile, but I think I remember David mentioning that overlay support in HD was on it's way, as only SD overlay was currently available. Is this still the case?

Full resolution overlay support at 1440x1080 is available in the current version of Aspect HD, but only when scrubbing (with de-interlace turned off.) We do have new features coming, so look for annoucements around the NAB time-frame.