Hi Scott,
Hope you are better soon.
I have recently purchased the Sigma "Bigma" 50 - 500 mm with a Nikon mount from a company through eBay (paypal) called Digital-Rev. They are based in Hong Kong so I had to import the lens, and pay the duty and vat on it (at the door). Digital-Rev refunded both of these amounts within 24 hours. I ended up with the duty paid - receipt, which made the lens's warranty valid here in the UK (as stated on the Sigma website).
With shipping the lens came to 495, as compared to 745 which was the price I was looking to pay here. The shipping was UPS, fully tracked - 3 working days. I also purchased a MAC 7 year warranty with the lens for an extra 10.00. Digital-Rev emailed the status of the lens at each stage, and answered my emails right away. The experience could not have been better. They also sell the 170 - 500 mm Sigma.
Purchasing through Papal was guaranteed, as was the credit card. The company's reputation on the Internet was also very high. Since then I have purchased 2 other lenses through them - with the same results. So I would not hesitate to recommend them.
Some of the other club members have purchased equipment through 7 DayShop
http://7dayshop.com/ based in Guernsey.
Does anybody have any other ideas?