Ray,
I seriously doubt you will find an iota of difference in the quality of product from all the designs out there!
The cook learns the cooker and adapts to it's personality and the meat really does not care!
If I were to build my ideal smoker it would have:
Primarily Stainless Steel construction.
Be a "vertical design" in the smoke chamber.
Run as long as I could ever want without refueling or fussing with the fire.
Allow a variety of properly seasoned clean wood flavors without maintaining a separate "wood yard" to produce and store them.
Allow temp control to just a couple of degrees.
Be super easy to clean.
I am not talented enough to design or build something like that, so I just bought it!
There are a ton of great designs in use.
The WSM design and it's big brother, the UDS, work very well. Simple to load and stabilize and little "fuss" as the cook progresses.
The Bandera design, especially if built bigger like Phil's MOAB or Midnight's cooker (do a search for those) have a lot going for them.
The traditional horizontal log burner looks "sexy" and is a mainstay in the BBQ world. Without "reverse flow", the various temp zones can be used to your advantage. With "reverse flow" (ala Lang), you can have a larger area of even temps if that is what you want.
The "stacked" cookers with the fire in a chamber below and/or separated from the smoke chamber work very well.
They only thing I would suggest is that you plan and build a "mid-size" smoker, whatever that means. If you are thinking small, it is cheaper and easier to just buy a WSM or small sheet metal horizontal from Wally World.
On the large side--no need to build a HUGE pit you will never use either. Waste of time and money.
But, do allow expansion in space from what you are doing now--Trust me, your needs will grow, not get smaller :lol:
Figure what you need, pick a design you like, and do it!
When you pick a design and do a cost projection--stop and take a look at the market. You may find that a couple of WSM's, a Spicewine, a Lang/Klose, or whatever may not be that far off your costs and are proven designs. No engineering needed!
Have fun!
TIM