There are a few sushi restaurants in Lausanne
As Mentioned the Restaurant Myò Sushi bar - more fusion than Japanese
The Sushi Zen in the Lausanne Palace hotel - very pricey, they have some unusual sushi like unagi/ camambert or tuna quail egg
There is also a sushi restaurant at the Beau rivage- Very expensive
The Restaurant Ko-An is in Lutry but have never tried it.

I found the best quality/price is the
Restaurant Le Jardin d'Asie
Avenue du Théâtre 7
1005 Lausanne/VD
021 323 74 84
they have sushi, tepanyaki and Chinese food
We eat there very often and the quality is always very good