There is no hardware unity supports which has byte limitations for single dimension arrays, not even if you target the iPhone 2g, the worst level of hardware supported I think.
Sure this isn't meant to be about a general coding in .NET and not in relation to Unity?
As for the question itself: Report a bug. Should definitely not appear as boolean but as normal text input field
in the meantime you can write a CustomEditor for your class which shows you a text field there to circumvent it