Yeeee, the same
Top Of Rack
CRS (eg 24x Etherent 1g + 2xSFP+) - in every rack
+
CRS (with eg 12xSFP+) - as a core, to agregate.
Wrote the same in
http://forum.mikrotik.com/t/crs-with-24-sfp/76751/1
- ccr as a router (routers, firewalls)
Nice MikroTik network. I hope it will be in near future 
Thanks