What evaluation board would be the best option to convert the ADXL206 output to 4mA to 20mA?
Maybe try looking at 4-20mA Drivers? Searching the product pages for these parts, I see evaluation boards available for the AD5750 and AD5420.
We also have current output DACs that could be used for generating 4-20mA. Just open the selection table for our Precision & General Purpose D/A Converters, add the parameter called 'Features', and then search for '4-20mA'. I see evaluations boards available for the AD5755, AD5755-1, AD5757, and AD5422.