Yeah, maybe the SD drive is the way to go after all. I really like having the SD slot though. Problem is that I have about 60-70 GB free on my computer. All I have are programs, my dropbox which is less than 5gb, and essential files. Mostly it's programs eating up the space though. I do a lot of video, which currently I do off a 1tb Lacie Thunderbolt/USB 3 drive. If I put the files on the computer and then on the drive it's an extra step. And I know it's being picky, but then I have a third step of deleting the original file, because moving from the SSD to the external or SD drive copies it, it doesn't actually move it.
So I guess what it comes down to is there are solutions, they're just not as easy as simply having a big internal drive.
However, if you guys don't think I'm going to notice much of an increase between the mid-2012 to a new one, there's probably no point in upgrading. Especially if you think the 13" will be that big of a downgrade. So maybe it is worth looking at upgrading the internal drive, which seems to be only a little more expensive than the other options.
I do appreciate all the help and suggestions. I'm still checking the thread, so keep offering them if you have them. That's why I posted here, because I'm sure others have contemplated the same things.
I really love the rMBP, I'm just trying to figure out what the best value will be for me. If I put a $500 drive in this and sell it next year, I won't get my money out of the drive. But if I keep it for a couple more years, I will. Decisions, decisions. Apple will make it a lot easier if they make a big change to the form factor.
The other thing that's keeping me from switching is I really prefer the old mechanical trackpad to the force touch one on the rMB. I've gotten used to it, but I still find the original more reliable.