I certainly like the idea of an 'identical' bow for back up, but the reality for me is I want to get to 100% trad hunting whether it be geese, deer, pigs, moose, etc. in a few years.
The way I look at it I want a bow that fits each hunting style/game needs. Best I can come up with is I need 3 different weight ranges...mid 40's small game, mid 50's for deer and hogs, and eventually mid 60's for bigger game I hope to hunt one day. (that would be 6 bows! - maybe you are on to something!)
By tweaking arrow weight and using only similarly efficient bow designs I plan to keep arrow speed within 10fps which should give me similar impact point out to 20-25 yds.
Since the mid-50#s bow is the most veratile, it will likely get the most milleage as back-up and primary...
That's the plan anyway. Just anopther thought on how to justify buying more bows...