Best 5ghz USB Adapter for use with wpa_supplicant and ubuntu 11.04?

[Curtis Larsen]

Hi,

I am working a on a project that requires 802.11n 5ghz USB wireless
adapters on ubuntu 11.04.  I will need about 100 clients.  I need to
use these for some performance testing, and I need to be able to
select the band to test as needed (Ex.  freq_list ...).  Sometimes
testing 802.11n 5ghz 40Mhz wide, and sometimes testing 802.11 2.4ghz
20Mhz wide.  So far, I am looking at the ar9170, but it appears linux
support has been abandoned for this here:
http://linuxwireless.org/en/users/Drivers   So, I am thinking RT3572
is the best.  Anyone disagree?  Why?

I have been happy with the AR928X chip in my laptop, and have been
able to use full 802.11n in 2.4ghz, and 5ghz bands, and I can control
this as I need to.  Will I be able to use all of the same features on
ubuntu with the RT3572?  Anyone know where to get a discount on these
by buying bulk?  Let me know.

Thanks,

Curtis