Any evidence suggesting that any consumer wireless technology may be harmful?

Nope.: A massive study in denmark followed 420, 000 cell phone users over 13 years and concluded that there was no evidence of any harmful effects. This is not surprising, given that no plausible hypothesis exists for how a cell phone could cause tissue damage. Of course it's impossible to prove that there is no potential for harm, but all sources of harm known or theorized to date are clearly excluded.

Yes: On may 31st 2011 - reversing its long-held position on the safety of wireless radiation from cell phones, wi-fi, and “smart” meters, the world health organization announced that it had re-classified such non-ionizing radiation as “possibly carcinogenic.” the organization’s international agency for research on cancer placed radiation from these devices in the same category as ddt & leaded gasoline.