Does anyone know if it’s possible to use the Dura-Ace Di2 climbing shifters with XT level Di2 in place of the normal XT Di2 shifter?

Depends which shifters you mean. Do a search on my old thread Di2 xtr for full info.

https://singletrackworld.com/forum/topic/di2-xtr-satellite-set-up/

Perfect, thanks for that.

I think I’ll give that a go as I really don’t like the standard XT shifter unit.

Crap aren’t they.

one word of caution. The satellite shifters have quite short cables so you may need cable extensions depending on bar width.

Also depends if you use a road under stem box or the offset xt/xtr display.

The R600 will also work if you want one shifter box on the right hand.

Have a look here

http://productinfo.shimano.com/#/com/3.2