A couple of suggestions.

[Brian Francois]

I have been using GnuCash for a couple of months now and I have a couple
of suggestions.  First is performance related.  I dumped about 12 years
of Quicken data into GnuCash.  The datafile is now over 10 megabytes,
without the daily stock data, and it takes a long time (several minutes)
for the GnuCash screen to appear, or to save and exit.  I am sure the
size of the data is the reason for the sluggishness.  Given that history
I would suggest some mechanism to trim the data.  Perhaps a tool that
would trim all data from selected accounts prior to some specified
date.  Even better trim the data dumping it into a file named
<datFileName>.pre.<specifiedDate>  (or something) then create some
mechanism to open and read a previous file if requested.

Another way to approach this problem would be to export data from a
specified date into a new file, which leads into the second
recommendation.  An export tool that is useful.  An export tool, dare I
make the comparison, like Quickens that allows selecting account(s) and
dates, or possibly all accounts for a given date.  Also it would be nice
to export data into a format that other programs could use.  You can
Import data from Quicken format so it would be nice if you could export
in a Quicken format as well.  Personally, I think it should handle
importing/exporting into Microsoft Money format as well (but that is
another issue).

I guess that's all 
-brian