If I have placed an item on my"items I am watching" list on eBay, it means that I am very interested in it, and if a seller pulls it to sell to some schmuck who can't wait till the end of the auction('cause the buyer probably knows that it will most likely sell for more than he is willing to bid)then,as a buyer I am going to be pissed.Why bother putting it up for auction if you are going to pull that crap?
It is unfair to others who may want to bid on your item and...from experience...I have found that the "please sell it to me"offer which has come in, NEVER has been higher than my final sale and I absolutely refuse to pull an auction as I find the practice to be unfair and unethical.
I mean...how would you feel if a seller pulled that stunt on you,especially if you were interested in something which perhaps you had been looking for for a long time? I mean....really...
If you want to do things that way then just list it under the BUY IT NOW feature.