So, wait a minute. I thought Paypal was blocking Bitcoin purchases? It looks like there are Linden Dollars regularly for sale on E-Bay as well. Why aren't more people selling Bitcoins on E-Bay?
I think the main reason is the price...If you put up an auction,you don't know what the final price will be,and it might end up being less than the exchange rate...
If you put up a buy it now option,at the current exchange rate,the rate might go up and you'll end up selling your coin for less..If the price goes down,no one will want to buy from you..
Furthermore,those bitcoins have to come from somewhere..unless the seller is mining to get his bitcoins he will need to get them from MtGox or similar.And to do that he needs to pay fees which he will then have to pass on to the buyer on ebay...Thus making them cost more...And finally he might only have a certain amount of bitcoins that he might want to sell over a large period of time,to keep an eye on the rate...
That been said,I would love to see more bitcoins on ebay...