How difficult was it to trade back then?
Signing up with bitcoinmarket.com required only a username, a password, and an e-mail address. You could add bids and asks to a simple order book. Matching offers were settled manually using Bitcoin escrow and PayPal.
Were there any 'big' trades of 10,000 or more?
I see some 10 000 BTC trades in the data I posted above. I remember there being a few 10 000 BTC offers on the order book when I started.
If you're in the mood to process/analyse the data then I'd love to see a chart.