The pattern for the Celtic Seas Vest comes from a book called 25 Gorgeous Sweaters for the Brand-New Knitter by Catherine Ham (Lark Books, 2000) At $17.95 it's quite reasonable (and at $14.00 new and as low as $4.19 used at amazon, it's an even better bargain.
The pattern is not called Celtic Seas Vest--I made that up, in honor of the Celtic-looking clasp I plan to put on it and the ocean-y colors of the Kureyon yarn. It's actually called Shawl Collar Vest. There's also a pattern called Shawl Collar Jacket done in garter stitch that's designed the same way.
The book includes simple patterns for 10 women's sweater, 4 vests, and 5 kids sweaters or vests, and most of them look both do-able and wearable.
One negative is that in order to keep them simple enough for the brand-new knitter, there is minimal shaping. I added decreases to my pattern in order to narrow the shoulders a bit. The original is basically just a square, and when I made a mock-up out of a piece of fleece, I could see that the shoulder look wasn't all that flattering. Most of the finished objects in the book are displayed either flat or on a clothes-rack, so the wide shoulders look ok, but on a real person, especially a person with hips, the angular look may not work out quite so well.
The sweaters with sleeves are all dropped-shoulder as well, which does make them easy to knit, but is not exactly high-style these days. But there are many ideas of how to adapt and adjust the patterns, and I think I will make a couple more sweaters from this book before I exhaust its usefulness.