Try selling a multi-server solution to an SME, and see what looks you get as you quote them for hardware, licensing, and CALs for each part. You won't be walking out the door with a PO.
I tend to follow the internationally recognised definition of an SME being 1-250 users...... quite a broad spectrum to tarnish with your SBS brush.
It would appear your experience is with the micro end of the market.
Irrespective of the size of the entity, also depends what your target vertical is. For a tiny hedge fund office, the cost of a basic (not OTT) multi-server solution is pocket money compared to what they'd loose through inability to close their deals during a market rally. Believe me, if you put SBS in there and it hindered them ..... they would no longer be your client, you wouldn't even have a chance to come in and fix it.