CyberChimps, a relatively well known (although not huge) theme developer already have some pretty good pricing on their themes and particularly theme bundles. At the moment they have a coupon code (received from their email newsletter) for 40% off their bundle prices, this takes their complete "Every Theme" bundle from USD$229 down to ~USD$130.
But it gets better. They have recently started offering a monthly "Plus" subscription for pro support, which while a recurring payment, can be cancelled at any time if you no longer need it. Along with benefits of improved developer support, you also get 50% off all purchases, including bundles, and it stacks with coupon codes.
By signing up for their "Plus" service, I have scored every theme for only USD$69 + $USD9 (Plus subscription). When a regular theme goes for between $40 and $80, this is pretty good for 15 responsive themes that also work well with WooCommerce.
Remember, if you don't want continuing support to cancel your subscription to "Plus" before a month is up (you can always sign up again later if you do need support).
I hope some fellow OzBargainers find this of interest.
Edit: Also note that the theme licenses are multi-use (including for commercial work), and extend to all future theme updates.
They also have free versions of their themes here http://profiles.wordpress.org/cyberchimps/
The themes in the bundles are Pro versions with extra features.