Above a certain point the impact with the atmosphere itself will likely destroy the object, such as with Tunguska.
There is a paper from 1991 on the subject
here, unfortunately you would need to purchase it.
Here is
another one from 1996, this one is free. Basically it concludes that anything moving over 28km/second will be vaporised in the impact with the atmosphere. It also goes into the likelihood of larger interstellar objects.
An interesting subject
Edit:
High geocentric velocity meteor ablation from 2005
Edit 2:
Meteoroids from outside the solar system (Click "Free fulltext article")