Confirming the delivery of e-mail messages

All,

Our company sends hundreds of reports out every day to different
customers (most are sent using ASC's SEQUEL/ESEND products and relayed
out via our Domino SMTP server).  Some are pretty lax about when they
receive them, but others DEMAND that they receive theirs by a certain
time of day.  We need some way of knowing that the important reports
are received before the mandated time so we can act accordingly.  I've
looked at a few ways to go about this, and I haven't found anything
good yet.

1.  Using Mail Routing Events in the Notes log (log.nsf).  Every time
I export data from this, it looks like it misses some messages.  I
just cannot find them at all.  I've heard other people mention that
log.nsf just does not catch everything.

2.  Using the MailTracker Store and the Reports.nsf database.  All
reports.nsf seems to generate are summary reports.  Even if it did
help us determine that some messages have not yet been delivered, it
doesn't tell us which ones were or were not delivered.  The actual raw
MTC files look promising (they are CSV files), but the Domino server
has them locked, so we can't do anything with them like a CPYFRMIMPF.

3.  Using DEBUG_OUTPUT.  From what I've seen of it, it looks just like
the console output, including the line breaks -- which will make
parsing it a pain in the neck.  And now, for some reason, I can't get
the output redirected to a file.

There's got to be something we can do that I don't know about. 
Barring that, is there another STMP server with better logging that we
can use just to relay mail out from RPG programs?

Thanks!

Mike E.