The original poster was from 2007, so I'm guessing he's already resolved this issue.
That said, he specifically mentioned self-defense. And I don't personally believe that long range can be maintained for any length of time if either party wants it to go closer. Whether it be MMA or a dustup at a bar, if someone's willing to press forward, I've yet to see anyone proficient enough at kicking to keep them out for very long. All it takes is one recoil on a kick and the other person can bulldoze in.
If self-defense is a priority, I believe you have to at least be somewhat comfortable at a closer range than that. I'm a 6'1" former taekwondoka, and I certainly didn't have the chops to keep people at bay if they weren't already inclined to do so.
I think, though, that sparring within our chosen styles often convinces us otherwise. Until we consider that, in sparring, we're often coming from the same school or style, and then matched up roughly according to size and experience level. Doing that creates an unspoken set of common understandings about what's going to happen next. I believe that accounts for what I've seen in a lot of sparring bouts, where neither party seems to be pushing their agenda. Instead, they take turns showcasing their favourite moves.
That's part of the value, to me, in mixed sparring matches, whether in a sporting format or no. Contending with the different agendas is vital.
There may be kickers out there so good that they could keep the bad guys away. But I'm doubtful, honestly.
Stuart