I started out doing a snake burn in my weber and now have a Hark electric smoking oven. Have modified it with an Auberins external thermostat and use charcoal in the burning tray to try to match the taste of the weber and have pretty much nailed it.

Will never be as good good as what you are planning but is failproof and set and forget

 My old man is right into it, he just has a vertical one that he made (he used an offset one and didn't like it). He has tried a lot of different chips. Now he just uses a sheoak blend. Or the trusty hickory. Jam is good for ribs. My fav is hot smoked chook or when the macks were on at Pt Gregory. 

the one in your pic looks pretty flash. I saw quite a few like that at the pork and cider festival in swan valley a wile back. Seemed to work. Bit expensive to buy IMO. Your on right track to build one.

I just run the "nipper kipper" gal job. Good for herring. Works but cheap and shit. Should get to building a stainless one soon. 

I do heaps of smoking meats, did some amazing coffee rubbed beef short ribs yesterday. Smoked them for 6.5hrs with hickory and a little mesquite. All mine is done in my Webers but I would like to move to an offset soon, will probably get the Hark Tri Fire. Two cooking chambers would be good but that is a hell of alot of meat to do in one go.

I have used a few different woods and they suit different meats - ie, hickory and mesquite for beef and lamb, apple, cherry and peach for pork and chicken. Nothing like cherry smoked chicken wings covered in Sweet Baby Rays Buffalo Wing Sauce.

Check out my instgram @urban_pit_master or #urbanpitmaster

Building an offset would be quite a task, but if you have the welding skills, go for it brother!

Don't hesitate if you have any questions Roddo. 

 I'm actually chowing down on some freshly smoke kransky and home-smoked cheese myself as I type this. I run a kamado joe for all my low and slow. Do a LOT of pork butts for 12 hours over lump charcoal. 
As far as building an offset, you want to use Feldons Calculator for sizings to get the best airflow etc. And choose between standard flow or reverse flow. 

Apple is my alltime favourite wood for ANY food i smoke. Goes so good on everything. Cherry comes a close second. Not a hickory or mesquite fan really. Cherry smoked beef back ribs..... droooooooooooooooool! 

All this helps considering I actually work at BBQs Galore haha :D 

Another option is the UDS or Ugly Drum Smoker, basically a modified 44 drum that you convert into an upright smoker. There is quote a few cheap conversion kits available and someone with welding / cutting knowledge should breeze it in.

Fair bit of cooking real estate inside due to the upright design. Based on the ProQ and Weber Smokey Mountain designs I would think, or maybe they are based on UDS? 

I have tasted some awesome que' out of these things, some BBQ team in the US recently took out one of the major comps with a UDS.

Was really reticent at trying it as I hate strong flavoured fish, it was bloody brilliant ....one word YUM

Good luck with your smoking plans ! 

 I got a Hark Texas pro pit.  Cooked big slab of ribs on the weekend using Jarrah wood which turned out alright.  

I got my hands on some almond wood so looking forward to giving that a try.  I've also read that people use the banksia cones you can collect just about everywhere, but I haven't tried that yet.  

 Thanks for all the info. Looks like there are a few ppl right into it. Once i get started i might do up a build thread for those interested just gotta work on the design now.

 Watch out for drunk mates and kids with the offset burner box....

That's a cracker of an offset! 
I still love my humble weber, snake method always turns out some nice low and slow for me, but I'd love to upgrade to something like that one day