Is there any portable LED light that does this? I will be using it attached to the hotshoe of my DSLR.
Have you thought about a reflector?
LED are nice but sun light is very strong annd LED panels wont do much you need like atleast a 10.000watt light output which with a HMI be more possible and LED wont get any where close to that they produce more like 100 to 500wattof light. A reflector be more what you need if you want to be more portable and have low budget.
You can buy such reflectors for example from www.kflect.com.
I have a DoP kit, but when you start with purchasing first just a couple of large sized reflectors it will actually be a low price investment that lasts for a long time.
You will be good for the most part. Do not take a simple mirror this will be too harsh.
Take a K-Flector 2, K-Flector 3, or K-Flector 4. Those diffuse the light more the higher the number.
It was also used on this workshop here: https://www.facebook.com/media/set/?set=a.529092550477856.1073741826.334397456614034&type=1
Cheers