ive got a ultegra 6600 front shifter only, its designed for triple, i seem to remember it being bodgeable to a double by limit screws on the derailleur, however not "ideal", as you end up with a third click that does nothing.
Shifter pretty good condition, not really used it much.
RRP is £200 for the pair, so £20 sounds fair for one on mates rates.
ill be back in town october 23rd onwards if you want it and dont mind the wait
[edit] I misread, i thought you were only looking for just the one shifter. To be honest the rear shifter is the hardest one to come by so buying just my front one wouldnt get you much closer to a set. Up to you.