Just received my first QI charger from Amazon. It is branded "Metrans" and called a "Super mini".
It only cost £20 in Europe and works fine with my N5.
http://www.amazon.co.uk/gp/product/B00DU8XZZQ/ref=s9_simh_gw_p23_d3_i1?pf_rd_m=A3P5ROKL5A1OLE&pf _rd_s=center-2&pf_rd_r=1XDH1EK2X1JD2V8BRECA&pf_rd_t=101&pf_rd_p =430153987&pf_rd_i=468294
US Amazon $35 US:
Amazon.com: Metrans Mwt03 Qi Certified Super Mini Design Wireless Power Charger for Nokia 920/820, HTC 8x, Google Nexus 4 (Black): Cell Phones & Accessories
I haven't had it for long, so can't comment on heat or speed yet. It is black, circular and rather small, with a diameter about half the length of the N5 (so just less than the width, box says 60mm x 11.8mm).
There is a blue LED that blinks during charging, and for a couple of other alerts. I will upload a photo shortly but so far, so good!