What is the J1772 charging current limit on your Leaf? If you want a truly "portable" unit, it is important to get an EVSE that has a built-in universal AC input and an adjustable current limiter. I would add to this the importance of a LONG output cord (25') to plug in the SAE 1772 charge port connector. These pre-requisites tend to narrow your choices for a "portable" EVSE. At the high end of the price scale is the JESLA as one possible choice. However, it is rather pricey at $1000.
Two other choices are the Open EVSE and JuiceBox.
They will cut down on the expense by as much as half the price of a JESLA, but are generally purchased by "DIYers", and do not have UL approval. I believe you will find that most, if not all "portable" EVSEs tend not to have UL approval, especially those that you can build yourself. However, I know that the JB can be purchased completely pre-assembled from EMW for about $100 extra, and EMW claims they are working on UL approval.
The standard input cord on a JB is longer than most at 6' and comes standard with a plug for a NEMA 14-50R (RV Park) outlet. EMW also sells short (~12" long), adaptor cords for other types of AC outlets including 120V, as well as 240V. A popular adapter for 240V is one that plugs in to a NEMA 10-30R, electric drier outlet. The latter can be quite useful when "opportunity charging" at a friend or relatives house, which again stresses the importance of a portable EVSE that has an adjustable current limiter. The current limiter adjustment on a JB can be set at intervals of 1A, from 0 to 60A, and this adjustment can be made external to the enclosure with the wireless key fob option.
For more info on the JB, here is the link to EMW's online store.
http://www.emotorwerks.com/products/online-store