TDS fiber is a fairly large provider with XGS-PON deployments.  They sell a 2Gbps synchronous service with the ONU having a 2.5G copper interface.  I have a couple Eero Pro 6E units on this service.  

Key piece is that it's a 10Gbps synchronous TDMA strand.  The 2Gbps might not be that common, but with typical oversells on 10G you can do a LOT of 500M and 1G plans. 

Ubiquiti has a product in alpha, I believe we can talk about it next month...

Also an interesting use case is an SFP+ OLT from Tibit feeting a pile of tower side radios on a single strand and a 8,16,or 32:1 splitter...    Or throw that OLT in a Siklu 8010 (10Gbps FDX 80Ghz radio) and feed the APs off the SFP+ ONU units...  I'm just waiting for a demo unit to get here to do a cambium v3000 3.5Gbps PTP shot to a group of WAVE APs and 2 450Ms.  Fun times.