I've smoked chicken quarters on the brinkmann charcoal smokers like the electric one posted above and it worked good. I did a boston butt on it and since it takes longer, the ash pan filled up too much. I was unable to remove the ash from the pan as new charcoal would go on top of it. There was no escape for the ashes. The electric would be great in that way.
But the last time I smoked a boston butt, I used my weber charcoal kettle girl. It has charcoal baskets you set to the side and the grate ends flip up to access the charcoal buckets to put more charcoal or wood chips in. And the ash just fell down the through the holes to the bottom of the girl without issue. The weber kettle grill can be used as a grill also.
Not sure of what you are talking about as small. All smokers Or any that I've seen have been a few feet tall. Would have to ride in the back of the truck unless you can dismantle. But then messy.