I need something much longer than one volume, the longer the better, where the romance is a mere subplot & the setting is not in a school. I'll even take a really strongly suggestive Bromance, like GetBackers & Hunter x Hunter.

Let me start you off with Fake. It's more plot-heavy than most BL, and even has a het side couple.

Some longer titles that are frequently recommended:
Banana Fish
These are all shounen-ai.

We have been here before. Try some of the suggestions in these posts:
Shounen-ai/Yaoi like this?
Recommendations 😕

This post under the heading Manga then the subhead Multiple volumes will direct you to more threads:
Before you start a new thread...

This old thread has a lot of good suggestions for Bromance type stories:
Pure Subtext

I think it's odd that you haven't been able to find anything not set in a high school in all the years you've been reading yaoi. There's actually quite a lot. You've had some bad luck!

Luo Xue Cheng Bai

Will add more if I recall.

It's way late to post a reply and you probably know this manga by now, but the manga, novel, and anime No. 6 doesn't center mainly around the romance, although it is there.

I like the point of this thread. Please keep the suggestions coming thank you

My favorite one is the novel mirage of blaze (honoo no mirage?). It isn't just about romance, but my god it's beautifully crafted. Will forever be memorable for me

try Cold Sands

it's just too good ;-; & i still can't get over it.

[img]http://i67.tinypic.com/2vbook7.png[/img]