The ports that are used for stacking are not required to be trunk ports.  They are only dedicated for stacking, and once two (or more) switches are stacked together, they become one logical switch.  Think of your stack as a single switch.  You will only need trunk ports to connect between the stack and the single unstacked switch.  Hope this helps. -B
Hello,  I have a question regarding trunking in combination with stacked switches. In my example I have two switches that are stacked, and an unstacked switch. I've placed all sales employees in VLAN 10 (first switch in stack) and the management employees in VLAN 20 (second switch in stack)  on the stacked switches. The servers are on VLAN 30 on the unstacked switch.  Do I need to assign trunkports between the two stacked switches in order to enable the stacked switches to communicate?  Thanks in advance!
Stacking and trunking