The "Coming Soon" Miami - Brickell Supercharger Station has been located by a member of the Tesla Motor Club forum and he reports that there are 25 charging stalls.  THEY ARE STILL UNDER CONSTRUCTION.

He reports that it is in  "the lower level of the Brickell City Centre underground parking garage in lots A2 (10 chargers below Saks 5th Ave) and C2 (15 chargers north side of the garage). The electrician I spoke with working on the installation estimated they’d be ready in a month.

This is a great location for people living/working in Brickell/downtown Miami, but visitors will have a hard time finding them. This garage is huge, so it’s unlikely there will be de-ICEing issues with these."

Here's the vicinity: (For a full size view, right-click image and open it in a separate tab or window.)

This is the first urban Supercharger location in Florida and appears to have a total of 25 charging stalls. Urban Superchargers have a lower capacity than Superchargers located along major highways, 72 kW versus 120 kW. 

Here's some additional photos that he took.

Update as of December 2, 2017.  

One of our club members reports the following progress:

The cabinets for the 10 chargers below Saks on level A2 are in place. The cables have not been installed although they are all present. All the equipment is physically installed but not connected. The site is not directly visible since it is covered with protective screening. I went behind, but could not take photos because my guide was exceedingly nervous that i was there at all.

The 13 cabinets on C2, Aisle 10 are being wired right now. there were several electricians working connecting the wiring. They would not allow photos either. They did say they expected to complete their work on both sides before December 15, including inspections after which FPL still must complete their connection and turn on power. The electricians said they and Swire Group (Brickell City Center is theirs) were intent on having them all working before Christmas.

Update as of December 30, 2017.

Despite the Tesla website showing an opening at the end of 2018, a recent photo shows that the A2 level looks to be nearing completion.

Update as of March 15, 2018

Current reports indicate that there are 10 Urban Type (72 kW) Supercharger stalls under construction on the A2 level of the parking garage and 13 on the C2 level. (Not 15 as previously reported.)

The Tesla website and the navigation systems in the Tesla fleet show that 13 Supercharger stall are now operational, indicating that the stalls are on the C2 level.  

Tesla is now referring to this location as Miami, FL - SW 7th Street,  rather than Miami, FL - Brickell.

Today a member on the Tesla Motors Club forum confirmed that the  13 Superchargers were operational and provided the following photo.

Presumably the remain 10 stalls will be energized at a later date.

Please note the green light on the charging port and the Urban style charging stall.

Update as of May 31, 2018.

The remaining 10 Urban Style Supercharger terminals have been energized.  Tesla now refers to this location as Miami - SW 8th St.