Innosilicon a4+ will get you 520-540mh/s and under 750w of power. Its not listed on the site but you can pre-order the a4 (minimum 3 units) and then choose to updgrade the pre-order to the a4+ when shipping time is ready. You will however have to pay possibly 1k usd more than the l3+ for the a4+. There is also another thread about this https://bitcointalk.org/index.php?topic=2140874.0