2.1 Update :: Lack Of Screen Lock Whilst In Call Screen?

With the old 1.6 software on my X10, the lack of an automatic screen lock when in an active call was mildly annoying, as not all areas of the screen were active. However, with the new 2.1, just about anywhere on the screen becomes active (especially when juggling two simultaneous calls). What are the chances that we'll see a 'lock screen' function for phone calls? Those of us who actually use the phone for phone calls whilst holding it would surely appreciate it. Other android devices have had this for years.