I have some experience with what you are talking about, so I can give my opinion, for what it's worth.
I was involved in Crew racing (Rowing) for some years after being a powerlifter for a long time. I noticed that I had much better power for the sprints (hill running/rowing sprints) than my colleagues/team-mates because of the powerlifting I had done, even after losing 60lbs to row.
You CAN train for power without hypertrophy (not much added mass). There are a lot of small guys that are very strong. Low reps, few sets, short workouts are best either way. 5 sets of 3, heavy on squats and deads (different days) may be good. Limited upper body movements, so that you don't put on unusable mass. IMO, you probably won't put on much size with all the cycling either way, unless you are genetically predisposed or you work on hypertrophy as a focus in the gym.
As far as AAS and others, you've got EPO as said above. Then Anavar, good for strength without size. Then EQ (Boldenone) which increases RBC count and is mildly anabolic for most people and is said to build tendons (though I've seen no data on this).
As an aside, I have known many runners/sprinters who use Winstrol (stanzolol). I don't know how this works however, as it is said to cause brittle tendons. But perhaps for someone not doing anaerobic work, it could be of some benefit.