I (thought) I actually found one of the authors of Sonia on Facebook (Marc Cohen). He didn't respond to my message.
There's a Marc Cohen that has/had a company in the UK called "All in Equity" (get it?) that declared $30k in revenue at some point. He seems to have dropped out of the poker world. Probably sold his idea for a few million and retired. I'd show you his Google+ profile, but I'm not sure he'd want it posted on a public forum.
I chatted briefly with Spears about Sonia on the old forum, we think she's actually modeling herself from her opponent's perspective, then solving some linear equation between her own (external) range and her opponent's. The authors mentioned she's technically a Bayesian model, but don't go into detail about how she functions. She did beat Polaris, which at the time was the strongest EQ (publicly known).