To alter the sleeve length, you might try just knitting it as directed, and stopping before you shape the cap. Try on the sleeve as best you can. It should reach to your under-arm. If it doesn't, keep knitting until you're there. Then, shape the cap. Count how many extra rows you did, and do the same with the other sleeve.
Or, you could add 4 inches of ribbing to the cuff, for a long, fold-over cuff, which, on you, may be a short fold-over cuff, or no fold at all! Although, if it's a bulky sweater, the folded cuff may not look as good.
Have fun! Good luck finding a pattern. You might take a peek at "Chunky Knits" if you really want the bulky, fast-knit type sweater.