This mod makes the transition between dimensions very smooth and adds a lot to the atmosphere of the game. I've seen many builds showing non-euclidean geometry, however, they need to use the nether as a proxy.

I propose a new block/structure (can be disabled in config), which allows portals to link to the same dimension. This would allow for extremely cool builds/bases.

There is also the possibility of integrating with a third-party portal mod (see #228)

Duplicate of #231

Though what you're asking is theoretically more than what would be required to fulfil #231, if I'm going to fix #231, I'm going to do it properly, i.e. no frame blocks, any 2D shape (just like the nether portal) and any destination (which, as far as I understand, is what you're asking for).
That'd be a creative-only solution though. I'd rather not get too much into survival balancing, so integrating with other mods is much preferred there (e.g. the one you mentioned, Random Portals, Portality, DimDoors, Gate of the Fold, Stargate Network, etc.).

Are you sure this is a duplicate of #231? Because this is mainly about same dimension portals, and not about the frame itself. Again, what you have done here is amazing and it would be a shame not to expand on it.

As I said, it's not an exact duplicate but any acceptable solution to either would solve both. Guess I can keep this open to make sure it actually does.

Oh, I would so enjoy Portality compatibility.
I recall seeing the mod a few times in the past, but I didn't consider using it due to focusing primarily on 1.7.10. It seems to solve an issue I was facing, though, which means I'll likely be using it.
EDIT: I'd especially enjoy compatibility, since it seems that Portality causes some crashes or infinite loading when going between dimensions with Better Portals.

I would just like to say that this is the one feature that I really want (and didn't realize that it wasn't already implemented).

I know that I could add on the Mekanism mod and use the Mekanism Teleporter in it, but I already have plenty of tech mods and just need the non-euclidean parts of this mod. (Both within the same dimension and between dimensions.)

I hope that this gets added someday.