Hi,
I recently upgraded to a wing and back plate for similar reasons, I was fed up with the clutter of a BCD. I went for the Apeks WTX40 wing and Apeks back plate and harness, the whole set up cost me about £220 so less than a buddy BCD. About 50% of my diving is on a single and 50% on twins so I got a single tank adapter from
Diving Products - Home. The whole set up works really well both with the single and the twin.
If you are planning on using your wing with a single tanks don't get a really big one as it will end up rapping round the tank and creating allot of drag in the water.
Tom