My solution to your problem is can only be used in the broswer window(firefox in this example)
I have made a way for this on Firefox and it is very hand I just select the text and execute the gesture to do the search(ie wikipedia, ebay... any search box)
FIRST you need firefox
SECOND you need to get ebay to be a quick search on firefox
to get ebay to be a quick search on FF here is what you do
1 go to ebay.com using firefox
2 right click on the search box on ebay and 'Add a keyword for this search...'
3 a small window will pop up fill the all the fields accordingly as below
name: Ebay Search
keyword: e (or what ever you prefer, e)
create in: where ever you want (Bookmarks by default)
(click OK to close the window)
now you just created a quick search on FF. To test if it works clear the address bar on FF and type 'e lightsaber' and it should come up with an Ebay 'lightsaber' search
THIRD once you got the quick search set up here is the Key strokes for the example , execute your gesture after selecting the text you want to search on ebay
[CTRL_DOWN]c[CTRL_UP][CTRL_DOWN]l[CTRL_UP]e[SPACE][CTRL_DOWN]v[CTRL_UP][ENTER]
this command basically tells firefox to
Copy[selected text],
Focus on the Adress bar(CTRL+L)
type 'e'
Put a SPACE
Paste[selected text]
ENTER
very handy :)
if you prefer sticking to Internet Explorer go here
http://searchy.protecus.de/en/ I guess this can also be modified
alternatively an ebay search could also be achieved using the 'search box' on FF,IE and Opera Browser, [I dont know how to achieve this on Opera but I believe it can be done]
if you are confused about making quick searches on FF go here:
http://www.sugarrae.com/creating-firefox-quick-search-bookmarks/