There is a pretty simple workaround for ‘library capacity’ and access using the iPad; admittedly, it involves bringing a laptop, but it should work.
If you have your iPad set to ‘sync with iTunes over Wi-Fi’ & ‘Manually manage music & videos’ [can be done under the ‘Summary’ tab for your device in iTunes, in the ‘Options’ section], you can drag & drop music onto your iPad without having to perform a full sync or be directly connected to the iPad. This will give you the ability to locate requests from your partiers on the laptop and transfer them to the iPad quickly; bring your entire library [in iTunes] and you can play what you need when you need it!
Special Note: You don’t need a ‘real’ Wi-Fi network to do this on a MacBook/Pro- you can use the ‘Create Network…’ option in the Wi-Fi settings on the laptop, select that newly created network in the iPad’s wi-fi settings, the iPad will show up in iTunes and it will work just the same!
