A motorcycle would be an impractical extravagance, but a cellular directional antenna isn't. Not with how web-dependent I am. And the antenna, along with the cable and adapters, costs a fraction of a motorcycle.
The cable is kind of a beast. It's about twice as thick as TV cable or even the bit of cable that comes out of the antenna. I usually have the back door open from the time I get up until I shut down for the night, so routing the cable won't be a problem most of the time. When it's wet or cold, though, I'll have to pinch it between the weatherstripping. I don't know if it will leak. The rest of the time (a.k.a. driving) the antenna and cable will come down and stow away.
this, and one like this. My Verizon JetPack rests in the booster cradle.