I got some help from Dell in understanding how to use the "ip helper" command from VLAN 30 to reach across and get DHCP from VLAN 40.  They also told me how to add all VLANs to the trunk ports between switches so the switches "talk VLANs" to each other.  

Where I'm a bit confused is how I make the workstation VLAN the "default."  In other words, if they have a vendor come in and plug in his laptop, I want him to be part of VLAN 30 and get a 192.168.30.x address.  I thought by simply tagging all non-server ports as VLAN 30, I'd be good to go.  But I've been told that a PC that plugs into a port assigned to VLAN 30 is going to get packets it doesn't understand, and that instead I'd somehow have to make VLAN 30 the default/untagged network to get DHCP requests to work properly.

The last paragraph I just wrote is where my eyes go crosseyed and I'm totally lost.  Any help/guidance would be appreciated!

Brian