On Mon, 10 Apr 2006 21:56:04 -0500, Cal Vanize
postulated :

The basic selection of aircraft for FS2004 is... well, basic.

That's the reason the net is full of add on aircraft for free and fee.

I'm looking for other options, particularly higher performance
single-engine cruising airplanes. The Mooney is OK, but are there any
others available?

Google is your friend.