Opinions wanted on new small office/warehouse server infrastructure

Greetings again all,

Continuing my adventure, I'd like to get some opinions on infrastructure for a new small office I'm helping to launch.

Here is the scenario, this is for a warehouse/distribution center that will have approximately 5-6 people in the office and a few truck drivers on the road. They are literally starting with nothing except a building which they just purchased. 

We still need to have some detailed discussions about what they are trying to accomplish, but here are the services I've identified they will need so far:

1. Database (SQL Server) for their warehouse management system
2. Web server to host an online portal for their drivers to access the WMS for pickups/deliveries. This portal is also accessed by their customers to view live inventory and place orders as well as view past orders/invoices (can download as PDFs). I'd estimate less than 50 people per day would be accessing the web site.
3. File server for document storage
4. Email
5. Phone service

I'm pretty certain email will be hosted Exchange. I'm thinking about a hosted phone service as well, but have not decided yet. If not, I am thinking about something like Elastix.

For the other services, I plan on virtualizing these workloads. Of those services the database and web server would probably be the most critical. I do not believe though that outage costs would outweigh the cost of an additional server for redundancy purposes. This is a conversation I still have to have with the owners, but based on my other experiences with setups like these, I am thinking a day of downtime if the server goes down will be acceptable. Ultimately I will have the following VMs:

1. DC/DHCP/DNS
2. File/print server
3. SQL Server
4. Web server
5. Phone server (maybe)

So for the server itself, I am thinking of a Dell (not sure if it will be tower or rack at this point; I haven't seen what their server room looks like or if they even have one). I'm thinking 32-64GB of RAM, a single hex-core CPU, and 4-6 HDDs in RAID 10. The HDDs are tricky. I do believe the database will run fine on 7200RPM drives (I will have to confirm with the developers first), but if it does, I'm wondering if I should go NL-SATA or just SATA.

As for the virtualization platform, I am leaning towards Hyper-V mainly so they don't have to pay an additional cost to get access to the backup APIs. They are a non-profit, so I will probably purchase a single 2012 Datacenter license for them from Techsoup so they don't have to worry about Windows server licensing if they want to add VMs in the future.

Server, workstations, and phones would connect to a 24-port switch, then to some type of UTM router/firewall (that can handle a DMZ for the web server), and then to the internet (thinking of just starting with business cable for now).

Not sure about backups yet. I know Unitrends has a good rep here and it does seem nice that you can virtualize on the appliance itself if the server goes down, but the smaller appliances look like they use small RAID 1 configs? I wonder if the workloads would even be usable like that? We use Veeam here and it is nice, it's just I would need a second server if I wanted to spin up VMs from backup if the primary host goes down.

OK, I am going to end this post now since it is getting rather long and I know there is a lot to chew on and think about and I'm sure I haven't touch on everything, but I will turn it over for discussion and hopefully some feedback. Appreciate any advice. Thanks!