I think the cost would far out weigh any benefit, and the only benefit I can think of is the carb is a much simpler technology, if I'm wrong or missing something please enlighten me.
Simplicity, flexibility. Fewer sensors to fail, dump the TBW garbage, no need to get your bike dyno tuned for $300+ minimum everytime you make a change of signiicance... Cooler running engine, better fuel mileage than the earlier non-O2 sensor EFI bikes.
Downsides exist of course. EFI is a bit better behaved when conditions change, ie altitude. nice cruise control integration. Current HD EFI is almost as smooth running as a carb and even the fuel mileage has improved with the use of the closed loop, assuming you're tuned to run in closed loop.
Sadly I agree that at this point cost does out weigh benefit. The other thing to think about is whether emissions testing will come to your state... No way you'd be able to pass a 'smog' test with a titled EFI vehicle equipped with a carb, visually and certainly not from an emissions stand point.
Of course these are just my opinions and based on my experience converting my '05. I converted it back to EFI when I traded it in btw... and have all the goodies waiting if I ever decide to pick up an earlier bike.