They're awesome vehicles, especially the V8 AWD models, for sure.
When it comes to pricing and sales, however, it's not far fetched to see that they don't sell that well because they stray a bit from the class norm, are quite pricey, etc.
But what that translates into is large discounts when new and expectedly more so with CPO or ex corp. exec. cars.
Case in point, here's a leftover white/beige LOADED V8 2007 model (so much stuff, the sticker is almost $60k) with $11k off. That's probably not uncommon, at all.
http://cgi.ebay.com/ebaymotors/NEW-0...QQcmdZViewItem
And another leftover, this time actually Pearl White & Beige, but no Sport package (i.e., not the best looking wheels...but still nice):
http://cgi.ebay.com/ebaymotors/BRAND...QQcmdZViewItem
Kind of like the Town Car, only not nearly as terrible, with nice discounts new and then lower with a few months and even just a few miles...the number of new 2007's around is pretty self explanatory.