When you say 'in the round' do you just mean seamless, or knit a tube and cut it? There's a big difference...
For a seamless vest, take a regular pattern and CO for both the back and fronts onto one needle. Then knit up to the underarms and divide so you knit the back and both fronts separately with the same shaping as in the original pattern. Keep the shoulder sts live instead of binding off and do a 3 needle BO.
sue- knitting heretic