I'm not sure about being knowledgeable specifically relating to high-end domains, but I do have a few domains for sale and have been buying and selling for around 14 years.

My highest price sale was Like.co.uk but I'm not permitted to disclose the amount - sorry!

Recent high-value sales can be seen here:
http://www.dnjournal.com/domainsales.htm

My latest sale to appear on there was VirtualKiwi.com for $4200 which can be seen here:
http://morganlinton.com/sedo-and-afternic-weekly-sales-charts-led-by-baristas-com/

My current list of around 400 domains is here:
http://bit.ly/domainlist

I'm looking for a good price for Fifties.com with it being a nice, generic .com domain name. If interested, let me know.