Also, the reentry vehicles for the Chinese FSW reconnaissance satellites used heat shields made from Oak.
[1] http://marsrover.nasa.gov/mission/spacecraft_edl_aeroshell.h...
Orbital reentry would last for minutes and at much higher velocities. The centrifugal forces generated by unchecked rotation could cause blackout or even death. You'd also need to figure out what happens if your heat shield is not heated evenly due to rotation.
Guided reentry is a solution, but then we're talking RCS thrusters, fuel tanks, guidance equipment -- maybe something you can strap onto a spacesuit, but approaching a spaceship. And then you need one for each astronaut, increasing weight and complexity.
I think that's what the comment is saying. He said it would be unobtanium or a lot, by which I assumed he meant the bulk.
Incidentally, the "unobtanium" comment is quite clueless. People have proposed making ablative heat shields out of wood, for heaven's sake. If you allow a "suit" to get bulky enough, an ablative heat shield in one is well within the realm of existing materials science.