Competitive, rectangular trampolines

[Neuffy]

So, I haven't been around much recently (lost this season to school and toenails), but teh intarwebs are useless.

Basically, I'd like to replace my old, worn-out round trampoline, and I'm wondering which rectangular competitive trampolines are recommended by members here. I'll be initially using it outdoors, in a yard with plenty of space (so it has to stand up to the elements, eg. not rust), but eventually will likely build an enclosure for it.

I know I want something reasonably high-end, but I don't really understand the physics of how trampolines work, and, as I said, google wasn't godly enough (or I'm lacking google-fu).

So:

1. Any recommended brands? Specific Models? Vendors in Canada? Particularly if one is involved in gymnastics.

2. Is it correct to say that the advantage of a rectangular trampoline is that you can have a fairly large area, but still have the most central areas within a relatively short distance of the nearest springs? If so, then does this mean that the most important thing is to minimize the width of the trampoline? As far as I have been able to gather, the ideal trampoline can be as long as one wishes, but will not be wider than ten or eleven feet. (And I've seen listings as low as seven feet maximum.) Is this correct?

3. Are there any other factors should should influence the decision?

Thanks in advance,

Neuffy