The Ethernets aren't any problem so long as they are 100 Mbps or better.
Let's assume that all the servers are connected to an Ethernet on the top floor. All the Ethernet clients are connected to an Ethernet devoted to each other floor. Pairs of WLAN bridges connect each lesser Ethernet to the top floor Ethernet.
If each bridge pair connects adjacent floors, then each WLAN link but the last (lowest) has to carry the traffic of multiple floors.
If each bridge pair connects the top floor with one other floor, then each WLAN link only has to carry the traffic of one floor.
I hope this helps. Thanks. /criss