*frowns*
Hmmm. I can see why there'd be a fixed limit (fixed array size, say, plus you don't want the system graph to have a hundred thousand edges...). You'd need a minimum of... 10 systems w/n 500LY (at max tech), since each can have a warp point to itself plus each of the others. And you'd need to create 100 warp points that way. If you think your opponents would try this, you can always use a sparser galaxy...
It's probably more practical to simply close off warp points, and create new ones stacked in the same square. The nice thing about this is that they can be defended w/ a single minefield, base and set of satellites; plus, since warping takes 1 MP, you can warp-warp-warp through a chain of always same-square warp points and perhaps traverse your empire in one turn. Bad news is, of course, if your defenses go down your attacker can traverse your empire in one turn.
I'm also tempted to look at warp-point booby-traps (e.g. create warp point in center of system you don't care about. Then create a black hole. Does the warp point remain, and if so, is black-hole damage on arrival or end-of-turn? Likewise, one with too much time on his hands could try to lure ships into systems with a black hole, then close all exits. Pity we can't create one-way warp points. ;-))
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-- The thing that goes bump in the night