No unfortunately i do not, me and a friend of mine are watching this already for a few years now and see the motor slowly develop.
The problems isn't in the motor anymore this has improved over the years and there are very good motors to find even for DIY conversion kits there are very nice options available which keep developing. I think the whole E-bike concept will have a great future for especialy city trafic.
The greatest problem at the time still is the battery
and it's lifecycle versus cost.. Using an e-bike on daily basis, need to recharge this battery on a daily basis. Those batteries have charge lifecycle, some have e.g. a life cycle of 250 recharges before they wear out. Also they do not wear out like over night, the performance slowly decreases. so after 150 load cycles it maybe still be on 50% capacity so the older it gets it shortens your radius of bikefun.
So ddepending on how you like to use the bike like once a week for fun, you'll might have a while a lot of fun. Us it on more regular basis you'll need say a new battery each year. And there is where the fun is spoiled, new batteries are still realy the almost the most expensive part in the E-bike up to €700 for a battery is still the average price.
So that would make e-biking with the initial purchase of the bike and the €700 + expenses yearly a rather expensive hobby..
Don't forget to add bike maintenance, i did mountain biking for many years and used rather a lot of brakes and chains and bearings and in those days even rims yearly, especialy on sandy routes by wet weather. Sand, greas and water, is polishing paste grinding through and destroying everything. If you do not take your bike completely apart 3 to 4 times a year to clean it from this sandy polishing paste inside everything. The expenses go up drasticaly.
Look at Kriedler e-bikes
they run with a bosch motor.. those bosch motors are very good..
For bike conversion motor look at the Bafang products, best cost effective way to convert an existing bike..
But truly it's the batteries that spoil the fun..
still..