You just mentioned a handfull, and I can think of a couple dozen more, but none are "sleepers" as you put it. Any of the big names in 1911 smithing will do a great job on a Delta, as they all have the requisite knowledge to work on pretty much any 1911 in any caliber out there. You just need to pick one that fits your criteria.
Though I've never handled a Yost outside his earlier Gunsite days, if I were in the market and I wanted it done in a reasonable amount of time, that's where I would send it, as I see guns being done all the time in less than a year. I guess is you have that many talented smiths in one shop, it stands to reason that work will get done a little quicker than a one man shop.
My personal favorite smith is Chuck Rogers. I suppose were I to have someone work on a Delta for me, that's where I would really want to send it in an ideal world. However, I imgaine that all the big name smiths are very backlogged. Best of luck sir.