Tex, here's a few suggestions:
1. The spinning bomb/paint brush trick already mentioned...
2. I saw an article where the writer actually 'dipped' the entire point of the bomb into yellow paint so that the whole nose was yellow. Then, he dipped it again in the 'bomb color' so cover up the yellow that was on the nose. He didn't dip as far on the second 'dip', so that some of the yellow still showed.
3. I've been meaning to try this one, but haven't had an opportunity yet. I have some clear decal film at home. I'm planning on painting a small section of the decal film yellow, then cutting out a 'strip' and applying it to the bomb. Should work, but I have not experience to know for sure.
M.