I found a best of both worlds scenario in a older Cannondale touring bike. It has similar geometry to a racing bike, light aluminum frame & drop handle bars, it deals nicly for my occasional need for speed. But, a longer sturdier frame, triple chain ring, heavier duty wheels, wider tires, all of which help distribute and remove the drag of my 40-pound daughter in a bike seat. (we are 220 together)
The combined attributes make for a quick and supportive ride as we cruse the trails, hit the assault or run over the occasional curb, while pulling a Burly trailer.