Ocelot, thanks for your kind words. Credit for the Anduril flow chart goes to containerfan. Im glad the marked up version I use for myself, is useful to you and others as well 
Until you find an HDS at a price you are less uncomfortable with, I would suggest an RRT-01. Maybe ask Skylumen if he can put an sw45k into one for you.
fwiw, 16340 works fine at the low outputs an HDS is intended for, but if small battery size works as an excuse to help you avoid opening your wallet, I support you in resisting.
fwiw, HDS is planning a new model that will be 18350 by default, but I have no idea if it will happen in Henry’s lifetime. So your wallet may remain safe for the foreseeable future. lol
another option is to buy the 18650 HDS on ebay, and ask Andy Zhu to put an sw45k into it for you ;-). You could probably resell or trade the 18650 tube for a stock 16340 tube… or even try to find someone who would trade you an 18350 tube…
fwiw, I just checked the price of a Rotary w sw45k and it is not $500, it is “just” $393 
maybe also try placing WTB ads… for an HDS w sw45k
forewarning, eventually you will open your wallet for an HDS… you could skip the expense of an RRT-01 by treating yourself to the HDS of your dreams, sooner than later 
The RRT-01 is a nice light in its own right, it might not stop you from wanting an HDS, but it could delay the impact on your wallet 
another option to consider… The TS10 in the above photos is modded to sw45k. I actually use the TS10 more than the HDS in the pics, which has an sw45k also.