*groan*
J&A, given the number of times we both have posted pictures and information about smart cars, I feel invisible.

To the OP: adding to what John & Angela have posted, there are 3 versions of the smart car (excluding the electric and CDI)
2000-2007 model 450
2008-2015 model 451
2016- ...... model 453
For each model there are 3 cars, the "Pure" (basic trim level), "Passion" (mid trim level), and "Cabrio" (convertible).
My 2009 smart fortwo Passion is a model 451.
smart cars have a 5 speed manual transmission, but do not have a clutch pedal. The computer does the shifting. smart cars are technically called an "automated manual". The smart CDI (diesel) is not offered for sale in the USA.
Prior to the model 453 the transmission had a single stage clutch. It can feel jerky when shifting. But it is easily remedied by feathering the gas pedal between shifts.
Beginning with the model 453, smart cars come with a DCT (dual clutch transmission) that shifts very smoothly. As of right now the model 453 is listed as NOT flat towable - because of the design of the DCT.
**UPDATE** 2/5/16 1:05 PM
I just checked the smartusa build-a-car web page. For 2016 there is a true manual transmission. The DCT is an upgrade. I was unaware that there is an option available.
In my signature is a link to my flickr photo albums. I have posted a lot of photos of my smart's towing set up and of some of the issues that I have encountered. A great many of the photos have detailed comments that I posted with the image.
As previously posted, the
smartcarofamerica forums are an excellent resource. It has a towing section, where I have also posted.