Buy the internal aluminum frame and never look back. Best investment for the tent period IMO. Tent is up within 10 minutes. YOu can get steel frame but aluminum is the way to go- alot lighter to pack.
Deluxe Wall Tents makes the frames for their tents. We bought one from them last season... 16x20x5 walls with custom 8' porch extension. Very nice setup.
My older tent (14x16x5)was purchased new in 1996 from Edmonton Tent & Awning - Oufitter deluxe model and we ordered the aluminum internal frame from Kwik Kamp I belive based in MOntana. We use to set up the tent in the mountains for winter sledding. Best investment. We use to do tohe tubing frame, but the threaded joints were a pain in the spring th take apart. After our tent, lots of guys went with the setup we had or tried their own with exhaust tubing and flange open the ends. Worked but a ##### to take apart also.
The only reason we got a new tent/frame was to have more room as our group of guys is now 7 from initially being 2.