I feel your paIn bro. I'm a painting contractor as well in a similar situation in my area. I've decided to go apesquat and ride the train for a while! But then again, I'm a single guy with far less responsibilities than the average family man would have. (and I'm really burnt out on painting.) I wish you the best in your decision.
Here is an example of what Pat is saying. These are just the guys that were picked up by Google as roof cleaners in NJ, not to mention the 100 other guys who are out there in your area that don't have internet presence or signed up with Google Places. Now the one guy you know about just turned into 20, and they don't mind traveling. I have guys coming 1 1/2 hours from New Jersey bidding on work in my area.
I would hold onto the painting gig as long as possible until you get your feet wet with the roof cleaning for a year or two. You won't have enough work to keep you full time right out of the gate. While there are many houses out there with roof stains, most homeownwers don't seem that bothered by it.
I'd say in your mass marketing let the pictures do the talking. no need to educate the public on HOW you treat roofs (focus on the value not the technique). I might be wrong here, but even mentioning "soft-washing" is missing the point, unless you have a major competitor who hard washes. Face to face is different, if a potential client is asking you how you do it, tell them, maybe 1 in 100 will think, "heck, I could do that". Of those, I bet you'll never run into someone with the guts to start their own business and be good enough to threaten your bottom line.
another thought, in my market, it does a world of difference to simply educate people that roofs CAN be cleaned/treated. Even the people that call me say stuff like "my shingles look worn, what is happening up there?".