Just thought I would share my experiences with three different setups on Windows and MACycle
1. Ethernet + Intel wireless (Win 7, Linux, although the OS is not really impt for this case)
Result: Failed
Explanation: Intel explicitly restricts mac spoofing, to the extent that even if the wireless adapter (Wi-Fi)'s mac is changed, the change is not propagated to the hostednetwork/miniport adapter. It was bad luck that I started testing with this setup which led to some confusion until I found a working setup in the next..
See
http://www.intel.com/support/wireless/wlan/sb/CS-031081.htm for more info
2. Ethernet + ASUS usb wifi dongle (XP)
Result: Succeeded
Explanation: No such rubbish for ASUS, although the steps varied a little (perhaps also because this is on XP). ASUS software can already configure the wireless adapter as a SoftAP (and shares the internet connection from the wired adapter), so all that remains is to set the ssid to attwifi (with passphrase), and rename the wireless adapter to Wi-Fi. MACycle had no problems rotating macs for Wi-Fi. hostednetwork is not applicable here and no need to configure ICS separately.
3. Ethernet (optional) + onboard Broadcom wireless (Win 7)
Result: Succeeded
Explanation: This was the closest to the instructions described here -
http://gbatemp.net/threads/homepass-chaldrons-mac-cycler-for-windows.352935/
except that only one network adapter is used (the Wi-Fi). Turns out that under Windows 7, the wireless adapter can still connect to regular networks while serving as SoftAP/hostednetwork, so this can work by having Wi-Fi itself share its internet connection to the miniport adapter. The downside is that the internet will be disrupted for normal activity every time the mac for Wi-Fi is changed, but for Streetpass purposes it is still perfectly fine.
NB: Ethernet was listed as I used it for initial testing and found it to be working, before realizing that it isn't essential.
Refer to
http://msdn.microsoft.com/en-us/library/windows/desktop/dd815243(v=vs.85).aspx for more info.