@Sean, are there any updates on this trial to find a solution? I bought a Raspberry Pi B+ to get get personal access to Mathematica and it works slowly but great, with the exception of many Wolfram-Alpha calls, due to the HW limitations of the Pi. So I registered for a 30 days trial period of Mathematica 10 in order to try out its capabilities and verify if it is worth ~150 per year for pure personal usage, with the result, that most Wolfram-Alpha calls ends up in a "ExportString is not available in this version of the Wolfram Language." error message. Even the simplest as "= GDP of Germany", which really do not provide any sophisticated or disclosed data at all, as well as most other freely available computed query results on the public Wolfram-Language web site, can not be accessed from within the Mathematica 10 trial edition.
Even though I appreciate of course, that there is a free trial version of Mathematica, which is not self-evident, I think you (as a representative of Wolfram Research in this forum) might agree, that this "inscrutable" limitation is somewhat frustrating while trying to examine whether Mathematica 10 is worth 150 / year for just personal mathematical playing around. :)