Sorry, if you already went through this, but it just came to my mind and i decided to share.
It's common way now to record close and far mics for orchestral libraries. There are many older libraries which lack this feature. So, may be it's good idea to give a new breath to those libraries by recording hall ambience to them, while (when) you record new stuff, in the same environment. It's like, you play samples on stage in position and record far mics for them. These samples (libraries) are already edited and i think there will not be very intensive programing for far miced samples. You then can sell it like add-on to existing libraries.
VOTA, SOV, LOP, some Brass, Strings and Piano libraries, CoolVibes and i think many more libraries will benefit from it.
PS: OK, VOTA2 already recording with Hall, but there still can be VOTA1 as entry lib (like VSL FE and VSL Pro).