The keys from wallet.dat can be read by pywallet, without any need for the blockchain.  A readly available tool to retrieve the keys from this file will likely be available for a very long time.

If you are talking relatively modest amounts, e.g., maybe $250 or less, of today's funds, you might want to simply buy a bitcoin gift card or Casascius physical coin:
 

 - https://www.giftcoin.net/card/ (not yet shipping)
 - http://www.casascius.com

You can always add bitcoins to them yourself after receiving them as well.

The risk is that the copies of the keys were not destroyed after production of the physical coin, or that somehow the key was compromised enroute so some people aren't comfortable with large amounts on these.

And if there are large amounts involved, it would only be prudent to do production of the paper bitcoin or offline wallet using a secure method, such as using an air-gap to the network, booted from a live CD or other bootable distribution.