I figure this is useful to the community at large, so I'll post the message I received from Ableton support:
If you'd like to upgrade from your Live 5 download version to the boxed version, you can purchase the box (with CD-Rom, manual and sample-CD) from us directly for USD/EUR 30 + shipping (The payment currency and the amount of shipping costs depend on your country of origin.)
And if you like to buy the T-Shirt you have to pay 14,90USD for it
To obtain the box and the T-Shirt, please send me your address your T-Shirt size, your Live 5 serial number and your credit card information to
orders@ableton.com or fax it to my hands at 0049 30 288 763 11.
Once I received all necessary information I will charge your credit card for the total amount and send the package to your place.