I honestly think I'll be OK with my 32GB, at least for a while. At the end of the day there aren't that many big Vita games I own (or the ones I do own I don't care enough for to have on my memory card at all times). I mostly just want my Vita on Henkaku to have full PSP and PS1 support. I hated that US Vitas had limits to certain PS1 games (like Spyro or Crash) and that certain PSP games were never made available digitally (like X-Men Legends 2, Marvel Ultimate Alliance, and Crisis Core).
Someday I might get the SD2Vita just to have my full collection on it at all times, but for now I have so many games to play across so many systems it's hard to think about having such a large library at my finger tips, haha.
I have one of these.
They are clunky and cheap, but they get the job done. Mine have a hole at the bottom for charging, though.
I've got that one along with another basic one and grip with R2/L2 buttons for the OG Vita (which I sold, so now I have a bunch of useless plastic grips, haha), and one of the R2/L2 grips for my Slim Vita.
I didn't find that any of them gave me the perfect grip i was looking for, unfortunately. I'm sure one is out there that I'd like, but I got tired of trying, and I honestly don't have that much trouble holding it naked, especially the Slim.