I recently started to use the newer tinyAVR 0/1 series of chips (which are really neat, by the way). I picked up the ATtiny416 xplained nano and the ATtiny817 xplained boards from Microchip via Digikey. Both of these boards come with programmers attached, but they don't support the high voltage programming which is needed if you want to make use of the UPDI pin (the same thing is true with the older ATtiny chips, like the ATtiny13 -- you need a HV programmer to be able to use the programming/reset line as an I/O).
To be totally honest, I bought this mostly because a) I thought it was a really cool design and b) I like to support fellow Canadian stores. However I did test it thoroughly upon arrival, and it does indeed allow you to get out of the normally "locked" state where the PA0 pin is used as an I/O. Definitely read the documentation: I was trying to burn the jtag2updi sketch to the Arduino Nano clone I was using as the programmer, and it just wouldn't recognize the Nano. This is because this board has a write protect pin (presumably to stop you accidentally flashing something to this board instead of the target board which is actually a really nice feature!). So just make sure you follow the steps -- once you do, it's very easy and it works flawlessly with Arduino.
I don't actually use the Arduino environment for programming, so I'm curious to see if I can use this on the command line in a Makefile (I'm almost 100% sure I can because Arduino just uses avrdude behind the scenes anyway). I'll update this review if I get around to testing that.
All in all, if you need a HV UPDI programmer for this series of chip, this one is well-designed, easy to use, and made in Canada!