especially considering maps such as valkora-blah's laborynth, I think that intra-star gates could be appropriate for either 1) a high enough level research (surely 8 would suffice) or said research and a costly add-on to every applicable gate. or finally, my personal favorite, 3) a high research and a really costly version of the phasegate

part of the Vasari code is to hit where the enemy is weakest, I've had more than enough games where I've succesfully bored by way through the enemy's soft internal solar system (Aeroleon sector is a great example) to grab a homeworld. The vasari really shouldnt have to go through all of the effort of having 2 bases in a given solar system to make full use of the phasegate technology.

in case anyone is curious this has been a concept long in the making, and I'm fully aware of the balance repurcussions of such a tool, but given proper counters (frankly I dont even believe those are nescessary) it really wouldnt be so bad, its very much a niche tool (and should be accordingly QUITE costly)

ah one last note: I would personally prefer that only one of these be buildable per star (to prevent their spamming) that way the enemy has a clear object worth striking, instead of being open to massive extra-solar attack from several sides.

in the end this only advances the vasari's original purpose: mobility one step beyond the enemy.