I feel your pain. I currently use a 9x20 HF, suitably modified, and it's fine. Not everything I want, but fine. A couple of things I'd like:
1. I'd like to do without change gears. Changing gears is a pain in the tush.
2. I'd like a more stable (as in ROCK SOLID) cross slide/compound. I've replaced the piddly plate that the cross slide was mounted on originally, and it's better, but not perfect.
3. I'd like less play in both the carriage and cross slide.
4. I'd like a real carriage lock.
5. I'd like a cam on the tailstock.
Never felt the need for a power cross slide. Never thought much of combo machines (I have definitely fallen in love with my Taig CNC mill, tho, and wouldn't want it on, around, or above my lathe).
While I, too, like the look of the South Bend 10, I think $5k for a lathe is exorbitant, especially as it's not USA made. Pretty, lovely fit and finish, to be sure, but there is as much lathe out there for far less. The Eisen 1236 is made in Taiwan, looks breathtakingly similar to the SB, costs far less and weighs more.
My limitations are as much a factor as anything else -- I can't import 220v into the shop without a major upgrade in service, and whatever I bring in or out has to be elevated up four steps and maneuvered around some corners. Any 12x36 will need an engine hoist and more young hands and strong backs than my wife and I can produce.
So I work my 9x20 which, as I said, is fine. I think the bottom line is that we all get used to working with both the benefits and limitations of what we have. Whatever you wind up with, take it apart as soon as you get it, put it back together again and get to know it intimately and, if your situation is anything like mine, offer continual thanks to the life partner who tolerates your obsessions. Find out exactly what it can do and what "work arounds" you will need to develop to honor its limitations (the lathe, not the life partner). Frankly, I've found that's where I have gotten most of my satisfaction ("Wow! I did it anyway!").
I'm no expert, but that's my $0.02.
Doug