Does anyone know if there is a way to easily display latitude and longitude
as degrees decimal minutes so that it is still a number? The starting point
could be decimal degrees or directly enter degrees decimal minutes. It is
relatively easy to display degrees minutes seconds using a time format, but I
can't see how to make a cell format that will display degrees and decimal
minutes.

It seems that with all the interest in using GPS devices and looking at the
globe via satellite imagery that Microsoft would be very interested in making
cell formats just for the variants of latitude and longitude as they have
done for time and dates.