I don't know if it'd be practical to do a 45-second IR. It would be difficult, at any rate. But there are algorithmic reverbs that are capable of doing it.
At a Lexicon demonstration the salesman claimed the PCM96 could do a 2-minute reverb. I remember thinking: why?
I think ValhallaDSP's Shimmer is probably capable of it, as it uses regeneration to keep the tail going forever.