I have had the same thought. I didn't measure the pit at Smitty's, but it looked to be about 4' wide and 4 foot high. The key to it working is the 4' square smoke stack at the intersection of the two pits, which protrudes through the roof. This creates a good draft.
Kreuz's has a metal top protruding over the end of the firebox which seems to diminish the amount of smoke that escapes.
I noticed that the section nearest the fire is too hot to use, but is necessary to the length calculation. Kreuz's pits are much longer than those at Smitty's so there is more cooking area.
Jim - Another transplanted Texan
Former KCBS CBJ
Large and Medium Big Green Eggs , Black 18.5" WSM, Blue Weber Performer - Stainless, Green Weber OTG Kettle , Brinkmann SnP Pro, and a Stainless UDS. One retired Portable Kitchen grill.
Red Thermapen, Maverick ET-732, EdgePro Apex Sharpener.
Avatar is the original 1951 Weber Kettle