@ceremcem , @fskreuz I asked @evs-chris because I remember at some point mentioning that he uses Ractive for business applications with many views, so I imagine he might have something in the works even though it might not be in 100% ready for general use.
my case is a bit weird, though it may work for insurance too as it's not too far off finance
I actually am not using a router
We're building a replacement for a massive desktop app using a very similar style, and there's a bit too much going on to tie everything together in the uri. Instead we have a hierarchy of semi-independent views that can load each other as needed, which allows for multitasking and cross reference.
Personaly, I still tend to use multiple old school pages and normal links because it's more stable/robust. If some grain of salt triggers an exception in your page, your whole SPA might fall flat, including the routing. With normal links, at least, you can still navigate.
The basic window components I'm using are available here. The menu on the left manages which views are available, and if they're already open, recalling then to the foreground. The demo doesn't really use it, but there's also typically an area of the menu for open root contexts, like "I'm editing this inventory", "processing a payment", and "computing a sale".
SPAs are a little dangerous, but you can keep in-progress stuff safely cached in local storage for recovery if necessary. Most of what I'm working with is a crap ton of data entry, so it's not too difficult to manage a restore is the user accidentally hits from or something manages to crash.
The really weird thing is that the windowing system can go mdi for really big screens, but it will also squish itself down to mobile fairly nicely. Why they wanted decent mobile support in a data entry-centric app, I'm not entirely sure, but give the people what they want. If you hit the square on the app bar of the demo on desktop, it will break out to mdi.