I happened to be on Rad's website today and saw two new roll-top liners which are basically bags made for both the small and large baskets. They are pricey at $79 and $109 respectively but for those who want something that just works I thought it was interesting. They still have their small and large basket bags ($49 and $59).
Small Basket Roll Top Liner: https://radpowerbikes.pxf.io/R5kvE7
Large Basket Roll Top Liner: https://radpowerbikes.pxf.io/dam1rQ
Interesting, but way too expensive for what they are - could just get a waterproof rafting/kayaking bag and a bungee cord to strap it down for $20 or less. I have the small basket bag and it's pretty good, includes some insulation which it seems these new bags do not.
Thanks for sniffing this out, Ryan; always good to keep up. I was expecting new-model bikes to be announced this year, but I bet production and shipping problems have put plans on hold unless competitors force their hand. Perfectly happy with my Mini ST, though.