Thanks for the help guys. Given this is my first build I think I should probably keep it simple. I found the Hoffman "Schedule 40" which is a 5F1/GA-5 circuit with an EL-84 and it looks really good as a starting point. I'm thinking about a few changes like two inputs for bright/dark (or humbucker/single coil), adding a pot to the NFB as a "gain" control, and switchable output for 4/8ohm speakers so I can use it with whatever I want. I'm afraid I probably won't be building it in PVC like the original but I did get a kick out of the fact that he did it. 
After I get a build under my belt I might tackle something bigger like an 18w, but it sounds like buying an attenuator is probably in order. I have heard good things about the Weber Mass series and they're cheaper than I expected. I like the fact that if I were to get one I could use it on any of my amps without needing to mod each one like I would with something like VVR.
TV,
I too have been struggling with volume control issues. I solved my issue in a couple of ways.
1. I bought a Maz 8, which is a fantastic amp, and a Dr. Z Therapy, which has a fantastic MV. Both of which can be played with great tones at very low volume.
2. I decided quite a while back that I wanted to learn as much about the nuances of different larger amps. The master plan was to learn about everything regarding amplified sound, which includes guitars, pedals, etc.
3. In order to control the volume on my project amps I invested in a Fryette Power Station. This is a 6l6 driven amplifier that operates as wonderful attenuator and you don't lose the tone as you turn down the volume. It is quite amazing.
4. In the photo I have the 18 Watt 6v6 Plexi almost wide open, and I learned that this amps wants to breathe at 12:00-3:00 on the volume control. With the Fryette Power Station I can dial the volume down to below bedroom level and have the amp cranked. The result is just as you would imagine, totally saturated tones that you could play in a TownHouse with neighbors.
5. I was afraid that the 18 Watt Plexi was going to be unusable because it was so loud. It is becoming a local favorite with some musician friends, this amp is the perfect size for a small performing band situation. I mounted a Dr. Z Brake Lite in the cab for on the spot attenuation. It works well but has a tendency to blanket your tone. However a few clicks will knock off a few db's and allow you to get into the Saturated Zone and not cut through everyone's ears.
6. I just completed the 18 watt 6V6 and it has turned out to be much better than anticipated.
7. I am working on the Hoffman Stout right now. That is a very nice amp from what I have heard and I am looking forward to good things. It's a pretty simple project without a whole lot of bells and whistles. I re-purposed a chassis and cabinet from a Blackheart 5 Watt. That has turned out to be a lot of work to cut and drill due to the chassis being 16 gauge steel.
8. I would look at ideas for an Amp Cradle to mount the chassis while you are working on it. I bought one from MojoTone and it has been a fantastic tool.
9. The Weber Mass is a good solution, but it is sort of unsatisfying at very low volumes. However, I am spoiled with the Power Station.
Have fun!
BV