A good set of rollers with a resistance unit should allow you to hit your LT wattage and then a good amount more. During the winter, I'm personally going to be doing 1 set of 2x20 a week, and maybe, MAYBE some 5minute reps at 120-30% of that. Most of the rest of it will be 60%, nice and constant.

I personally don't plan on burying myself and passing out on the trainer/rollers this winter. I plan on being in great base and LT shape come February, and letting racing take care of the rest. I'll be working for the team so it's not imperative that my sprint be at an all time high.