the smaller the drop-in the more speed you have to sacrifice, thats simple math, you potential energy gets transferred into kinetic energy, so translated: lower = less speed, higher = more speed.
however if you refer to small drop-in as in minimalistic, easy to move, transport, etc...
You might want to consider making a drop-in from a ladder, im sure there are pics somewhere around here, basically it were two ladders in A-frame construction and a small horizontal platform on top, supported by two support beams running down onto one of the steps of the ladder (i hope you understand what i mean) it looked sketchy but very practical and sweet design...