I have been listing on UK site for about a year and state in my auctions that I accept payment in USD, GBP, and Euro. However, I believe you can list on the UK site for example and while your listing price will appear in Pound Sterling you can specify Paypal payment in US dollars. Buyers can make payment via Paypal in their local currency and have Paypal convert to US dollars. That way your buyer would incur the conversion expense. I have a paypal accounts in all three currency, however,I find some foreign buyers do pay in US dollars. I have not had to convert my Sterling or Euro currency, I use it when I travel. I have paid for airline tickets in Sterling directly from my Paypal account and also Paypal offers an ATM/Debit card which is great for traveling. Since I have not had to convert, I have not investigated how competitive Paypal conversion rates are but it seems it would be in their best interest to offer competitive conversion.
I will also confirm that your original Ebay ID is valid on all other Ebay sites with no problem and you can monitor all auctions on Ebay.com. In other words when you view "Items I'm Selling" from My Ebay, you will see all items for .com, .uk, .au listings.
Thanks for the input, I missed Ebay Live as we were in Europe at the time, so I appreciate knowing that I can view video online. I'll check that out.