Probably increasing their margin to minimize margin calls lately. They did this a long time ago with the oil futures - and never went back to the intra-day margin rates.
Other brokers have been increasing margins. TradeStation ended their $1000 intraday margin for eminis. 2 weeks ago there was this post about RCG: "yes, cme raised ES margins to $5,063 per contract. RCG even doubled that to $10,126 for the ES. anyone have a similar experience?" Imagine that, ES margin double what IB requires.
There was a broker that was an advertiser on ET called Efficient Executions, they had lower rates than IB for stocks. I am pretty sure they take Canadian customers but you should ask to make sure. Their website is www.efficientexecutions.com
FlatIrontrading.com the lowest! I am with them remote, I know they offer remote access for Canadian traders. I believe their site is down at the moment.