Its been a while since Ive researched this, but I dont think anyone has yet confirmed that the Magic Scorpion tube is interchangeable with the BTU Shocker (although it seems that it should be). More reading here: BTU Magic Scorpion 50/250 Watt Hotwire Halogen Review (The Fire Starter)
Ikon in post #42 (from this thread) mentioned that the TK75 tube might be an easy mod candidate
I keep thinking about a long/heavy modded Shocker (4S3P 18650) with triple XHP35 HI (7.5A @16.8V for about 1.5 hours total run time). But at that point, a remote pack would probably make more sense.
There also exists aluminum tube stock with similar ID & OD dimensions to the Shocker tube. The stock Shocker tube could be bisected and a section could be added. If threading isnt an option, a step could be cut into each tube section on a lathe and then compression fitted and staked. It would look pretty good with a polished center.
For light weight, constant duty, long range, remote lighting chores, its often hard to beat this: 8000 lumen 100 watt HID handheld spotlight conversion.
Please let us know if you come up with something else.