Thanks everyone. I’ve learned a good bit - maybe I’m the last person to discover dpc latency data on notebookcheck.net. It’s a little laborious to go through the site but worth it. The data strongly correlates with anecdotal stories about machines that work/don’t work.
Laptops from MSI and Lenovo tend to exhibit mostly low latency, which explains why, among the big manufacturers, you hear about these two for audio. However, not all MSI and Lenovo models appear to be low risk so you still have to research individual models. Some HP models appear to be good i.e. Elitebook 1050. Dell appears to be the most consistently troublesome for audio (i.e. the highly rated XPS line).
If I were buying new/off the shelf and had to buy today, I’d probably get either a Lenovo X1 Extreme for about $1800, the P72 17.3" workstation is a lot of machine for $1500 (but ~8 lbs) and a lot of folks are buying the P52.
If I didn’t care about TB3 I might get an MSI Raider for about $1500. If I wanted low-cost I might get an MSI Leopard for $1000 and take some risk on the plastic case durability. The MSI P65 is interesting at around $1450 and includes TB3 although I can’t find one to see it locally yet.
Dedicated graphics cards are such a common source of problems, to the point where folks disable these cards and use whatever basic Intel graphics is on the motherboard.
The 8750h processor appears to be a major winner for audio (and everything). Not much point in risking some expensive high-end graphics card for audio - more likely a problem than benefit and the big difference between gaming and audio.
This is interesting if you haven’t seen it: