Every prebuilt 27 inch wheelset I've seen are all heavy lower end wheels with straight gauge spokes and cheaper hubs. I have an '86 Univega Nuovo Sport and this year I'm going to upgrade it to an Ultegra 6500 group w/ 9 speed downtube shifters. I'm going to order a wheelset from Pro Wheel Builder with Velocity Dyad 27in rims, DT Comp spokes and some modern 130 hubs. I've ordered wheels from them before and if they have the parts in stock the turnaround is like 3-4 weeks. You select each part you want and it will give you the total price, weight and estimated turnaround time and you can send them your own hubs to build up if desired.

They also have VO rims if you want to run wider tires, both come in a 36.

https://www.prowheelbuilder.com/rims/shopby/27in.html